Upgrade bignumber.js version

46 files changed, 110 insertions, 110 deletions

diff --git a/packages/assert/src/index.ts b/packages/assert/src/index.ts
index 2d28d51e1..b9a04686a 100644
--- a/packages/assert/src/index.ts
+++ b/packages/assert/src/index.ts
@@ -12,7 +12,7 @@ export const assert = {
     },
     isValidBaseUnitAmount(variableName: string, value: BigNumber): void {
         assert.isBigNumber(variableName, value);
-        const isNegative = value.lessThan(0);
+        const isNegative = value.isLessThan(0);
         assert.assert(!isNegative, `${variableName} cannot be a negative number, found value: ${value.toNumber()}`);
         const hasDecimals = value.decimalPlaces() !== 0;
         assert.assert(
diff --git a/packages/asset-buyer/src/utils/buy_quote_calculator.ts b/packages/asset-buyer/src/utils/buy_quote_calculator.ts
index fcded6ab1..9205678e7 100644
--- a/packages/asset-buyer/src/utils/buy_quote_calculator.ts
+++ b/packages/asset-buyer/src/utils/buy_quote_calculator.ts
@@ -22,7 +22,7 @@ export const buyQuoteCalculator = {
         const remainingFillableMakerAssetAmounts = ordersAndFillableAmounts.remainingFillableMakerAssetAmounts;
         const feeOrders = feeOrdersAndFillableAmounts.orders;
         const remainingFillableFeeAmounts = feeOrdersAndFillableAmounts.remainingFillableMakerAssetAmounts;
-        const slippageBufferAmount = assetBuyAmount.mul(slippagePercentage).round();
+        const slippageBufferAmount = assetBuyAmount.multipliedBy(slippagePercentage).integerValue();
         // find the orders that cover the desired assetBuyAmount (with slippage)
         const {
             resultOrders,
@@ -43,7 +43,7 @@ export const buyQuoteCalculator = {
             const multiplierNeededWithSlippage = new BigNumber(1).plus(slippagePercentage);
             // Given amountAvailableToFillConsideringSlippage * multiplierNeededWithSlippage = amountAbleToFill
             // We divide amountUnableToFill by multiplierNeededWithSlippage to determine amountAvailableToFillConsideringSlippage
-            const amountAvailableToFillConsideringSlippage = amountAbleToFill.div(multiplierNeededWithSlippage).floor();
+            const amountAvailableToFillConsideringSlippage = amountAbleToFill.div(multiplierNeededWithSlippage).integerValue(BigNumber.ROUND_FLOOR);
 
             throw new InsufficientAssetLiquidityError(amountAvailableToFillConsideringSlippage);
         }
@@ -131,7 +131,7 @@ function calculateQuoteInfo(
         zrxEthAmount = findEthAmountNeededToBuyZrx(feeOrdersAndFillableAmounts, zrxAmountToBuyAsset);
     }
     // eth amount needed to buy the affiliate fee
-    const affiliateFeeEthAmount = assetEthAmount.mul(feePercentage).ceil();
+    const affiliateFeeEthAmount = assetEthAmount.multipliedBy(feePercentage).integerValue(BigNumber.ROUND_CEIL);
     // eth amount needed for fees is the sum of affiliate fee and zrx fee
     const feeEthAmount = affiliateFeeEthAmount.plus(zrxEthAmount);
     // eth amount needed in total is the sum of the amount needed for the asset and the amount needed for fees
@@ -168,9 +168,9 @@ function findEthAmountNeededToBuyZrx(
                 order,
                 makerFillAmount,
             );
-            const extraFeeAmount = remainingFillableMakerAssetAmount.greaterThanOrEqualTo(adjustedMakerFillAmount)
+            const extraFeeAmount = remainingFillableMakerAssetAmount.isGreaterThanOrEqualTo(adjustedMakerFillAmount)
                 ? constants.ZERO_AMOUNT
-                : adjustedMakerFillAmount.sub(makerFillAmount);
+                : adjustedMakerFillAmount.minus(makerFillAmount);
             return {
                 totalEthAmount: totalEthAmount.plus(takerFillAmount),
                 remainingZrxBuyAmount: BigNumber.max(
diff --git a/packages/asset-buyer/src/utils/order_provider_response_processor.ts b/packages/asset-buyer/src/utils/order_provider_response_processor.ts
index 4244d196c..f08cd6150 100644
--- a/packages/asset-buyer/src/utils/order_provider_response_processor.ts
+++ b/packages/asset-buyer/src/utils/order_provider_response_processor.ts
@@ -109,11 +109,8 @@ function getValidOrdersWithRemainingFillableMakerAssetAmountsFromOnChain(
                 return accOrders;
             }
             // if the order IS fillable, add the order and calculate the remaining fillable amount
-            const transferrableAssetAmount = BigNumber.min([traderInfo.makerAllowance, traderInfo.makerBalance]);
-            const transferrableFeeAssetAmount = BigNumber.min([
-                traderInfo.makerZrxAllowance,
-                traderInfo.makerZrxBalance,
-            ]);
+            const transferrableAssetAmount = BigNumber.min(traderInfo.makerAllowance, traderInfo.makerBalance);
+            const transferrableFeeAssetAmount = BigNumber.min(traderInfo.makerZrxAllowance, traderInfo.makerZrxBalance);
             const remainingTakerAssetAmount = order.takerAssetAmount.minus(orderInfo.orderTakerAssetFilledAmount);
             const remainingMakerAssetAmount = orderUtils.getRemainingMakerAmount(order, remainingTakerAssetAmount);
             const remainingFillableCalculator = new RemainingFillableCalculator(
diff --git a/packages/asset-buyer/src/utils/order_utils.ts b/packages/asset-buyer/src/utils/order_utils.ts
index 1cc2cf95f..3ea3cafd3 100644
--- a/packages/asset-buyer/src/utils/order_utils.ts
+++ b/packages/asset-buyer/src/utils/order_utils.ts
@@ -9,8 +9,8 @@ export const orderUtils = {
     },
     willOrderExpire(order: SignedOrder, secondsFromNow: number): boolean {
         const millisecondsInSecond = 1000;
-        const currentUnixTimestampSec = new BigNumber(Date.now() / millisecondsInSecond).round();
-        return order.expirationTimeSeconds.lessThan(currentUnixTimestampSec.plus(secondsFromNow));
+        const currentUnixTimestampSec = new BigNumber(Date.now() / millisecondsInSecond).integerValue();
+        return order.expirationTimeSeconds.isLessThan(currentUnixTimestampSec.plus(secondsFromNow));
     },
     isOpenOrder(order: SignedOrder): boolean {
         return order.takerAddress === constants.NULL_ADDRESS;
@@ -20,43 +20,43 @@ export const orderUtils = {
         const remainingMakerAmount = remainingTakerAmount
             .times(order.makerAssetAmount)
             .div(order.takerAssetAmount)
-            .floor();
+            .integerValue(BigNumber.ROUND_FLOOR);
         return remainingMakerAmount;
     },
     // given a desired amount of makerAsset, calculate how much takerAsset is required to fill that amount
     getTakerFillAmount(order: SignedOrder, makerFillAmount: BigNumber): BigNumber {
         // Round up because exchange rate favors Maker
         const takerFillAmount = makerFillAmount
-            .mul(order.takerAssetAmount)
+            .multipliedBy(order.takerAssetAmount)
             .div(order.makerAssetAmount)
-            .ceil();
+            .integerValue(BigNumber.ROUND_CEIL);
         return takerFillAmount;
     },
     // given a desired amount of takerAsset to fill, calculate how much fee is required by the taker to fill that amount
     getTakerFeeAmount(order: SignedOrder, takerFillAmount: BigNumber): BigNumber {
         // Round down because Taker fee rate favors Taker
         const takerFeeAmount = takerFillAmount
-            .mul(order.takerFee)
+            .multipliedBy(order.takerFee)
             .div(order.takerAssetAmount)
-            .floor();
+            .integerValue(BigNumber.ROUND_FLOOR);
         return takerFeeAmount;
     },
     // given a desired amount of takerAsset to fill, calculate how much makerAsset will be filled
     getMakerFillAmount(order: SignedOrder, takerFillAmount: BigNumber): BigNumber {
         // Round down because exchange rate favors Maker
         const makerFillAmount = takerFillAmount
-            .mul(order.makerAssetAmount)
+            .multipliedBy(order.makerAssetAmount)
             .div(order.takerAssetAmount)
-            .floor();
+            .integerValue(BigNumber.ROUND_FLOOR);
         return makerFillAmount;
     },
     // given a desired amount of makerAsset, calculate how much fee is required by the maker to fill that amount
     getMakerFeeAmount(order: SignedOrder, makerFillAmount: BigNumber): BigNumber {
         // Round down because Maker fee rate favors Maker
         const makerFeeAmount = makerFillAmount
-            .mul(order.makerFee)
+            .multipliedBy(order.makerFee)
             .div(order.makerAssetAmount)
-            .floor();
+            .integerValue(BigNumber.ROUND_FLOOR);
         return makerFeeAmount;
     },
     // given a desired amount of ZRX from a fee order, calculate how much takerAsset is required to fill that amount
@@ -64,9 +64,9 @@ export const orderUtils = {
     getTakerFillAmountForFeeOrder(order: SignedOrder, makerFillAmount: BigNumber): [BigNumber, BigNumber] {
         // For each unit of TakerAsset we buy (MakerAsset - TakerFee)
         const adjustedTakerFillAmount = makerFillAmount
-            .mul(order.takerAssetAmount)
-            .div(order.makerAssetAmount.sub(order.takerFee))
-            .ceil();
+            .multipliedBy(order.takerAssetAmount)
+            .div(order.makerAssetAmount.minus(order.takerFee))
+            .integerValue(BigNumber.ROUND_CEIL);
         // The amount that we buy will be greater than makerFillAmount, since we buy some amount for fees.
         const adjustedMakerFillAmount = orderUtils.getMakerFillAmount(order, adjustedTakerFillAmount);
         return [adjustedTakerFillAmount, adjustedMakerFillAmount];
diff --git a/packages/asset-buyer/test/buy_quote_calculator_test.ts b/packages/asset-buyer/test/buy_quote_calculator_test.ts
index fdc17ef25..cf443bef3 100644
--- a/packages/asset-buyer/test/buy_quote_calculator_test.ts
+++ b/packages/asset-buyer/test/buy_quote_calculator_test.ts
@@ -234,7 +234,7 @@ describe('buyQuoteCalculator', () => {
             const expectedEthAmountForAsset = new BigNumber(50);
             const expectedEthAmountForZrxFees = new BigNumber(100);
             const expectedFillEthAmount = expectedEthAmountForAsset;
-            const expectedAffiliateFeeEthAmount = expectedEthAmountForAsset.mul(feePercentage);
+            const expectedAffiliateFeeEthAmount = expectedEthAmountForAsset.multipliedBy(feePercentage);
             const expectedFeeEthAmount = expectedAffiliateFeeEthAmount.plus(expectedEthAmountForZrxFees);
             const expectedTotalEthAmount = expectedFillEthAmount.plus(expectedFeeEthAmount);
             expect(buyQuote.bestCaseQuoteInfo.assetEthAmount).to.bignumber.equal(expectedFillEthAmount);
@@ -272,7 +272,7 @@ describe('buyQuoteCalculator', () => {
             const expectedEthAmountForAsset = new BigNumber(50);
             const expectedEthAmountForZrxFees = new BigNumber(100);
             const expectedFillEthAmount = expectedEthAmountForAsset;
-            const expectedAffiliateFeeEthAmount = expectedEthAmountForAsset.mul(feePercentage);
+            const expectedAffiliateFeeEthAmount = expectedEthAmountForAsset.multipliedBy(feePercentage);
             const expectedFeeEthAmount = expectedAffiliateFeeEthAmount.plus(expectedEthAmountForZrxFees);
             const expectedTotalEthAmount = expectedFillEthAmount.plus(expectedFeeEthAmount);
             expect(buyQuote.bestCaseQuoteInfo.assetEthAmount).to.bignumber.equal(expectedFillEthAmount);
@@ -282,7 +282,7 @@ describe('buyQuoteCalculator', () => {
             const expectedWorstEthAmountForAsset = new BigNumber(100);
             const expectedWorstEthAmountForZrxFees = new BigNumber(208);
             const expectedWorstFillEthAmount = expectedWorstEthAmountForAsset;
-            const expectedWorstAffiliateFeeEthAmount = expectedWorstEthAmountForAsset.mul(feePercentage);
+            const expectedWorstAffiliateFeeEthAmount = expectedWorstEthAmountForAsset.multipliedBy(feePercentage);
             const expectedWorstFeeEthAmount = expectedWorstAffiliateFeeEthAmount.plus(expectedWorstEthAmountForZrxFees);
             const expectedWorstTotalEthAmount = expectedWorstFillEthAmount.plus(expectedWorstFeeEthAmount);
             expect(buyQuote.worstCaseQuoteInfo.assetEthAmount).to.bignumber.equal(expectedWorstFillEthAmount);
diff --git a/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts
index ad42cfd4f..cd79a0e5d 100644
--- a/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/erc20_token_wrapper.ts
@@ -271,7 +271,7 @@ export class ERC20TokenWrapper extends ContractWrapper {
         const tokenContract = await this._getTokenContractAsync(normalizedTokenAddress);
 
         const fromAddressBalance = await this.getBalanceAsync(normalizedTokenAddress, normalizedFromAddress);
-        if (fromAddressBalance.lessThan(amountInBaseUnits)) {
+        if (fromAddressBalance.isLessThan(amountInBaseUnits)) {
             throw new Error(ContractWrappersError.InsufficientBalanceForTransfer);
         }
 
@@ -327,12 +327,12 @@ export class ERC20TokenWrapper extends ContractWrapper {
             normalizedFromAddress,
             normalizedSenderAddress,
         );
-        if (fromAddressAllowance.lessThan(amountInBaseUnits)) {
+        if (fromAddressAllowance.isLessThan(amountInBaseUnits)) {
             throw new Error(ContractWrappersError.InsufficientAllowanceForTransfer);
         }
 
         const fromAddressBalance = await this.getBalanceAsync(normalizedTokenAddress, normalizedFromAddress);
-        if (fromAddressBalance.lessThan(amountInBaseUnits)) {
+        if (fromAddressBalance.isLessThan(amountInBaseUnits)) {
             throw new Error(ContractWrappersError.InsufficientBalanceForTransfer);
         }
 
diff --git a/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts b/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts
index 1ff130a48..c35b24664 100644
--- a/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts
+++ b/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts
@@ -39,7 +39,7 @@ export class AssetBalanceAndProxyAllowanceFetcher implements AbstractBalanceAndP
                     nestedAssetDataElement,
                     userAddress,
                 )).dividedToIntegerBy(nestedAmountElement);
-                if (_.isUndefined(balance) || nestedAssetBalance.lessThan(balance)) {
+                if (_.isUndefined(balance) || nestedAssetBalance.isLessThan(balance)) {
                     balance = nestedAssetBalance;
                 }
             }
@@ -81,7 +81,7 @@ export class AssetBalanceAndProxyAllowanceFetcher implements AbstractBalanceAndP
                     nestedAssetDataElement,
                     userAddress,
                 )).dividedToIntegerBy(nestedAmountElement);
-                if (_.isUndefined(proxyAllowance) || nestedAssetAllowance.lessThan(proxyAllowance)) {
+                if (_.isUndefined(proxyAllowance) || nestedAssetAllowance.isLessThan(proxyAllowance)) {
                     proxyAllowance = nestedAssetAllowance;
                 }
             }
diff --git a/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
index f374d509b..4b75ea386 100644
--- a/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
+++ b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
@@ -72,10 +72,10 @@ export class ExchangeTransferSimulator {
         }
         const balance = await this._store.getBalanceAsync(tokenAddress, from);
         const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, from);
-        if (proxyAllowance.lessThan(amountInBaseUnits)) {
+        if (proxyAllowance.isLessThan(amountInBaseUnits)) {
             ExchangeTransferSimulator._throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
         }
-        if (balance.lessThan(amountInBaseUnits)) {
+        if (balance.isLessThan(amountInBaseUnits)) {
             ExchangeTransferSimulator._throwValidationError(FailureReason.Balance, tradeSide, transferType);
         }
         await this._decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits);
diff --git a/packages/contract-wrappers/src/utils/utils.ts b/packages/contract-wrappers/src/utils/utils.ts
index 0b3270e78..ab69385e7 100644
--- a/packages/contract-wrappers/src/utils/utils.ts
+++ b/packages/contract-wrappers/src/utils/utils.ts
@@ -7,13 +7,15 @@ import { constants } from './constants';
 export const utils = {
     getCurrentUnixTimestampSec(): BigNumber {
         const milisecondsInSecond = 1000;
-        return new BigNumber(Date.now() / milisecondsInSecond).round();
+        return new BigNumber(Date.now() / milisecondsInSecond).integerValue();
     },
     getCurrentUnixTimestampMs(): BigNumber {
         return new BigNumber(Date.now());
     },
     numberPercentageToEtherTokenAmountPercentage(percentage: number): BigNumber {
-        return Web3Wrapper.toBaseUnitAmount(constants.ONE_AMOUNT, constants.ETHER_TOKEN_DECIMALS).mul(percentage);
+        return Web3Wrapper.toBaseUnitAmount(constants.ONE_AMOUNT, constants.ETHER_TOKEN_DECIMALS).multipliedBy(
+            percentage,
+        );
     },
     removeUndefinedProperties<T extends object>(obj: T): Partial<T> {
         return _.pickBy(obj);
diff --git a/packages/contract-wrappers/test/ether_token_wrapper_test.ts b/packages/contract-wrappers/test/ether_token_wrapper_test.ts
index e3efef19d..cc2419aa2 100644
--- a/packages/contract-wrappers/test/ether_token_wrapper_test.ts
+++ b/packages/contract-wrappers/test/ether_token_wrapper_test.ts
@@ -116,7 +116,7 @@ describe('EtherTokenWrapper', () => {
             const preETHBalance = await web3Wrapper.getBalanceInWeiAsync(addressWithETH);
 
             const extraETHBalance = Web3Wrapper.toWei(new BigNumber(5));
-            const overETHBalanceinWei = preETHBalance.add(extraETHBalance);
+            const overETHBalanceinWei = preETHBalance.plus(extraETHBalance);
 
             return expect(
                 contractWrappers.etherToken.depositAsync(wethContractAddress, overETHBalanceinWei, addressWithETH),
@@ -153,7 +153,7 @@ describe('EtherTokenWrapper', () => {
             );
 
             expect(postWETHBalanceInBaseUnits).to.be.bignumber.equal(0);
-            const expectedETHBalance = preETHBalance.add(depositWeiAmount).round(decimalPlaces);
+            const expectedETHBalance = preETHBalance.plus(depositWeiAmount).integerValue(decimalPlaces);
             gasCost = expectedETHBalance.minus(postETHBalance);
             expect(gasCost).to.be.bignumber.lte(MAX_REASONABLE_GAS_COST_IN_WEI);
         });
@@ -165,7 +165,7 @@ describe('EtherTokenWrapper', () => {
             expect(preWETHBalance).to.be.bignumber.equal(0);
 
             // tslint:disable-next-line:custom-no-magic-numbers
-            const overWETHBalance = preWETHBalance.add(999999999);
+            const overWETHBalance = preWETHBalance.plus(999999999);
 
             return expect(
                 contractWrappers.etherToken.withdrawAsync(wethContractAddress, overWETHBalance, addressWithETH),
diff --git a/packages/ethereum-types/package.json b/packages/ethereum-types/package.json
index 953b323c6..bd3748058 100644
--- a/packages/ethereum-types/package.json
+++ b/packages/ethereum-types/package.json
@@ -37,7 +37,7 @@
     },
     "dependencies": {
         "@types/node": "*",
-        "bignumber.js": "~4.1.0"
+        "bignumber.js": "~8.0.2"
     },
     "publishConfig": {
         "access": "public"
diff --git a/packages/instant/src/components/order_details.tsx b/packages/instant/src/components/order_details.tsx
index 4db20b13e..3ded50652 100644
--- a/packages/instant/src/components/order_details.tsx
+++ b/packages/instant/src/components/order_details.tsx
@@ -77,7 +77,7 @@ export class OrderDetails extends React.PureComponent<OrderDetailsProps> {
     }
 
     private _hadErrorFetchingUsdPrice(): boolean {
-        return this.props.ethUsdPrice ? this.props.ethUsdPrice.equals(BIG_NUMBER_ZERO) : false;
+        return this.props.ethUsdPrice ? this.props.ethUsdPrice.isEqualTo(BIG_NUMBER_ZERO) : false;
     }
 
     private _totalCostSecondaryValue(): React.ReactNode {
@@ -156,7 +156,7 @@ export class OrderDetails extends React.PureComponent<OrderDetailsProps> {
         return !_.isUndefined(assetTotalInWei) &&
             !_.isUndefined(selectedAssetUnitAmount) &&
             !selectedAssetUnitAmount.eq(BIG_NUMBER_ZERO)
-            ? assetTotalInWei.div(selectedAssetUnitAmount).ceil()
+            ? assetTotalInWei.div(selectedAssetUnitAmount).integerValue(BigNumber.ROUND_CEIL)
             : undefined;
     }
 
diff --git a/packages/instant/src/constants.ts b/packages/instant/src/constants.ts
index bfd9e9098..d407925a3 100644
--- a/packages/instant/src/constants.ts
+++ b/packages/instant/src/constants.ts
@@ -21,7 +21,7 @@ export const NPM_PACKAGE_VERSION = process.env.NPM_PACKAGE_VERSION;
 export const DEFAULT_UNKOWN_ASSET_NAME = '???';
 export const ACCOUNT_UPDATE_INTERVAL_TIME_MS = ONE_SECOND_MS * 5;
 export const BUY_QUOTE_UPDATE_INTERVAL_TIME_MS = ONE_SECOND_MS * 15;
-export const DEFAULT_GAS_PRICE = GWEI_IN_WEI.mul(6);
+export const DEFAULT_GAS_PRICE = GWEI_IN_WEI.multipliedBy(6);
 export const DEFAULT_ESTIMATED_TRANSACTION_TIME_MS = ONE_MINUTE_MS * 2;
 export const MAGIC_TRIGGER_ERROR_INPUT = '0€';
 export const MAGIC_TRIGGER_ERROR_MESSAGE = 'Triggered error';
diff --git a/packages/instant/src/containers/selected_erc20_asset_amount_input.ts b/packages/instant/src/containers/selected_erc20_asset_amount_input.ts
index cb9df527e..4b9993332 100644
--- a/packages/instant/src/containers/selected_erc20_asset_amount_input.ts
+++ b/packages/instant/src/containers/selected_erc20_asset_amount_input.ts
@@ -84,7 +84,7 @@ const mapDispatchToProps = (
         // reset our buy state
         dispatch(actions.setBuyOrderStateNone());
 
-        if (!_.isUndefined(value) && value.greaterThan(0) && !_.isUndefined(asset)) {
+        if (!_.isUndefined(value) && value.isGreaterThan(0) && !_.isUndefined(asset)) {
             // even if it's debounced, give them the illusion it's loading
             dispatch(actions.setQuoteRequestStatePending());
             // tslint:disable-next-line:no-floating-promises
diff --git a/packages/instant/src/redux/async_data.ts b/packages/instant/src/redux/async_data.ts
index 884ab103d..f20fe319f 100644
--- a/packages/instant/src/redux/async_data.ts
+++ b/packages/instant/src/redux/async_data.ts
@@ -99,7 +99,7 @@ export const asyncData = {
         if (
             !_.isUndefined(selectedAssetUnitAmount) &&
             !_.isUndefined(selectedAsset) &&
-            selectedAssetUnitAmount.greaterThan(BIG_NUMBER_ZERO) &&
+            selectedAssetUnitAmount.isGreaterThan(BIG_NUMBER_ZERO) &&
             buyOrderState.processState === OrderProcessState.None &&
             selectedAsset.metaData.assetProxyId === AssetProxyId.ERC20
         ) {
diff --git a/packages/instant/src/util/asset.ts b/packages/instant/src/util/asset.ts
index 709561dbc..a6fd77d5a 100644
--- a/packages/instant/src/util/asset.ts
+++ b/packages/instant/src/util/asset.ts
@@ -104,8 +104,9 @@ export const assetUtils = {
         return assetDataGroupIfExists[Network.Mainnet];
     },
     getERC20AssetsFromAssets: (assets: Asset[]): ERC20Asset[] => {
-        const erc20sOrUndefined = _.map(assets, asset =>
-            asset.metaData.assetProxyId === AssetProxyId.ERC20 ? (asset as ERC20Asset) : undefined,
+        const erc20sOrUndefined = _.map(
+            assets,
+            asset => (asset.metaData.assetProxyId === AssetProxyId.ERC20 ? (asset as ERC20Asset) : undefined),
         );
         return _.compact(erc20sOrUndefined);
     },
@@ -114,15 +115,15 @@ export const assetUtils = {
             const assetName = assetUtils.bestNameForAsset(asset, 'of this asset');
             if (
                 error instanceof InsufficientAssetLiquidityError &&
-                error.amountAvailableToFill.greaterThan(BIG_NUMBER_ZERO)
+                error.amountAvailableToFill.isGreaterThan(BIG_NUMBER_ZERO)
             ) {
                 const unitAmountAvailableToFill = Web3Wrapper.toUnitAmount(
                     error.amountAvailableToFill,
                     asset.metaData.decimals,
                 );
-                const roundedUnitAmountAvailableToFill = unitAmountAvailableToFill.round(2, BigNumber.ROUND_DOWN);
+                const roundedUnitAmountAvailableToFill = unitAmountAvailableToFill.integerValue(2, BigNumber.ROUND_DOWN);
 
-                if (roundedUnitAmountAvailableToFill.greaterThan(BIG_NUMBER_ZERO)) {
+                if (roundedUnitAmountAvailableToFill.isGreaterThan(BIG_NUMBER_ZERO)) {
                     return `There are only ${roundedUnitAmountAvailableToFill} ${assetName} available to buy`;
                 }
             }
diff --git a/packages/instant/src/util/format.ts b/packages/instant/src/util/format.ts
index 4adb63e21..eef332d3c 100644
--- a/packages/instant/src/util/format.ts
+++ b/packages/instant/src/util/format.ts
@@ -25,16 +25,16 @@ export const format = {
         if (_.isUndefined(ethUnitAmount)) {
             return defaultText;
         }
-        let roundedAmount = ethUnitAmount.round(decimalPlaces).toDigits(decimalPlaces);
+        let roundedAmount = ethUnitAmount.integerValue(decimalPlaces).toDigits(decimalPlaces);
 
-        if (roundedAmount.eq(BIG_NUMBER_ZERO) && ethUnitAmount.greaterThan(BIG_NUMBER_ZERO)) {
+        if (roundedAmount.eq(BIG_NUMBER_ZERO) && ethUnitAmount.isGreaterThan(BIG_NUMBER_ZERO)) {
             // Sometimes for small ETH amounts (i.e. 0.000045) the amount rounded to 4 decimalPlaces is 0
             // If that is the case, show to 1 significant digit
             roundedAmount = new BigNumber(ethUnitAmount.toPrecision(1));
         }
 
         const displayAmount =
-            roundedAmount.greaterThan(BIG_NUMBER_ZERO) && roundedAmount.lessThan(minUnitAmountToDisplay)
+            roundedAmount.isGreaterThan(BIG_NUMBER_ZERO) && roundedAmount.isLessThan(minUnitAmountToDisplay)
                 ? `< ${minUnitAmountToDisplay.toString()}`
                 : roundedAmount.toString();
 
@@ -62,7 +62,7 @@ export const format = {
         if (_.isUndefined(ethUnitAmount) || _.isUndefined(ethUsdPrice)) {
             return defaultText;
         }
-        const rawUsdPrice = ethUnitAmount.mul(ethUsdPrice);
+        const rawUsdPrice = ethUnitAmount.multipliedBy(ethUsdPrice);
         const roundedUsdPrice = rawUsdPrice.toFixed(decimalPlaces);
         if (roundedUsdPrice === '0.00' && rawUsdPrice.gt(BIG_NUMBER_ZERO)) {
             return '<$0.01';
diff --git a/packages/instant/src/util/gas_price_estimator.ts b/packages/instant/src/util/gas_price_estimator.ts
index 332c8d00a..9792b60ba 100644
--- a/packages/instant/src/util/gas_price_estimator.ts
+++ b/packages/instant/src/util/gas_price_estimator.ts
@@ -35,7 +35,7 @@ const fetchFastAmountInWeiAsync = async (): Promise<GasInfo> => {
     const gasPriceInGwei = new BigNumber(gasInfo.fast / 10);
     // Time is in minutes
     const estimatedTimeMs = gasInfo.fastWait * 60 * 1000; // Minutes to MS
-    return { gasPriceInWei: gasPriceInGwei.mul(GWEI_IN_WEI), estimatedTimeMs };
+    return { gasPriceInWei: gasPriceInGwei.multipliedBy(GWEI_IN_WEI), estimatedTimeMs };
 };
 
 export class GasPriceEstimator {
diff --git a/packages/instant/src/util/maybe_big_number.ts b/packages/instant/src/util/maybe_big_number.ts
index 9d3746e10..f48473389 100644
--- a/packages/instant/src/util/maybe_big_number.ts
+++ b/packages/instant/src/util/maybe_big_number.ts
@@ -18,7 +18,7 @@ export const maybeBigNumberUtil = {
     },
     areMaybeBigNumbersEqual: (val1: Maybe<BigNumber>, val2: Maybe<BigNumber>): boolean => {
         if (!_.isUndefined(val1) && !_.isUndefined(val2)) {
-            return val1.equals(val2);
+            return val1.isEqualTo(val2);
         }
         return _.isUndefined(val1) && _.isUndefined(val2);
     },
diff --git a/packages/order-utils/src/exchange_transfer_simulator.ts b/packages/order-utils/src/exchange_transfer_simulator.ts
index 06621fd9e..922ae8e17 100644
--- a/packages/order-utils/src/exchange_transfer_simulator.ts
+++ b/packages/order-utils/src/exchange_transfer_simulator.ts
@@ -88,14 +88,14 @@ export class ExchangeTransferSimulator {
                 }
                 const balance = await this._store.getBalanceAsync(assetData, from);
                 const proxyAllowance = await this._store.getProxyAllowanceAsync(assetData, from);
-                if (proxyAllowance.lessThan(amountInBaseUnits)) {
+                if (proxyAllowance.isLessThan(amountInBaseUnits)) {
                     ExchangeTransferSimulator._throwValidationError(
                         FailureReason.ProxyAllowance,
                         tradeSide,
                         transferType,
                     );
                 }
-                if (balance.lessThan(amountInBaseUnits)) {
+                if (balance.isLessThan(amountInBaseUnits)) {
                     ExchangeTransferSimulator._throwValidationError(FailureReason.Balance, tradeSide, transferType);
                 }
                 await this._decreaseProxyAllowanceAsync(assetData, from, amountInBaseUnits);
diff --git a/packages/order-utils/src/market_utils.ts b/packages/order-utils/src/market_utils.ts
index fa32f1413..9042551fa 100644
--- a/packages/order-utils/src/market_utils.ts
+++ b/packages/order-utils/src/market_utils.ts
@@ -52,7 +52,7 @@ export const marketUtils = {
         const result = _.reduce(
             orders,
             ({ resultOrders, remainingFillAmount, ordersRemainingFillableMakerAssetAmounts }, order, index) => {
-                if (remainingFillAmount.lessThanOrEqualTo(constants.ZERO_AMOUNT)) {
+                if (remainingFillAmount.isLessThanOrEqualTo(constants.ZERO_AMOUNT)) {
                     return {
                         resultOrders,
                         remainingFillAmount: constants.ZERO_AMOUNT,
@@ -137,7 +137,7 @@ export const marketUtils = {
             (accFees, order, index) => {
                 const makerAssetAmountAvailable = remainingFillableMakerAssetAmounts[index];
                 const feeToFillMakerAssetAmountAvailable = makerAssetAmountAvailable
-                    .mul(order.takerFee)
+                    .multipliedBy(order.takerFee)
                     .dividedToIntegerBy(order.makerAssetAmount);
                 return accFees.plus(feeToFillMakerAssetAmountAvailable);
             },
diff --git a/packages/order-utils/src/order_state_utils.ts b/packages/order-utils/src/order_state_utils.ts
index 389419587..430178b5d 100644
--- a/packages/order-utils/src/order_state_utils.ts
+++ b/packages/order-utils/src/order_state_utils.ts
@@ -214,10 +214,10 @@ export class OrderStateUtils {
         const remainingFillableTakerAssetAmountGivenTakersStatus = orderRelevantTakerState.remainingFillableAssetAmount;
 
         // The min of these two in the actualy max fillable by either party
-        const fillableTakerAssetAmount = BigNumber.min([
+        const fillableTakerAssetAmount = BigNumber.min(
             remainingFillableTakerAssetAmountGivenMakersStatus,
             remainingFillableTakerAssetAmountGivenTakersStatus,
-        ]);
+        );
 
         return fillableTakerAssetAmount;
     }
@@ -260,8 +260,8 @@ export class OrderStateUtils {
             traderAddress,
         );
 
-        const transferrableTraderAssetAmount = BigNumber.min([traderProxyAllowance, traderBalance]);
-        const transferrableFeeAssetAmount = BigNumber.min([traderFeeProxyAllowance, traderFeeBalance]);
+        const transferrableTraderAssetAmount = BigNumber.min(traderProxyAllowance, traderBalance);
+        const transferrableFeeAssetAmount = BigNumber.min(traderFeeProxyAllowance, traderFeeBalance);
 
         const orderHash = orderHashUtils.getOrderHashHex(signedOrder);
         const filledTakerAssetAmount = await this._orderFilledCancelledFetcher.getFilledTakerAmountAsync(orderHash);
@@ -312,7 +312,7 @@ export class OrderStateUtils {
             const tokenAddress = decodedAssetData.tokenAddress;
             balances[tokenAddress] = _.isUndefined(initialBalances[tokenAddress])
                 ? balance
-                : balances[tokenAddress].add(balance);
+                : balances[tokenAddress].plus(balance);
         } else if (assetDataUtils.isMultiAssetData(decodedAssetData)) {
             for (const assetDataElement of decodedAssetData.nestedAssetData) {
                 balances = await this._getAssetBalancesAsync(assetDataElement, traderAddress, balances);
@@ -335,7 +335,7 @@ export class OrderStateUtils {
             const tokenAddress = decodedAssetData.tokenAddress;
             allowances[tokenAddress] = _.isUndefined(initialAllowances[tokenAddress])
                 ? allowance
-                : allowances[tokenAddress].add(allowance);
+                : allowances[tokenAddress].plus(allowance);
         } else if (assetDataUtils.isMultiAssetData(decodedAssetData)) {
             for (const assetDataElement of decodedAssetData.nestedAssetData) {
                 allowances = await this._getAssetBalancesAsync(assetDataElement, traderAddress, allowances);
diff --git a/packages/order-utils/src/order_validation_utils.ts b/packages/order-utils/src/order_validation_utils.ts
index ae4291ea8..95215d918 100644
--- a/packages/order-utils/src/order_validation_utils.ts
+++ b/packages/order-utils/src/order_validation_utils.ts
@@ -31,13 +31,13 @@ export class OrderValidationUtils {
         if (denominator.eq(0)) {
             throw new Error('denominator cannot be 0');
         }
-        const remainder = target.mul(numerator).mod(denominator);
+        const remainder = target.multipliedBy(numerator).mod(denominator);
         if (remainder.eq(0)) {
             return false; // no rounding error
         }
 
         // tslint:disable-next-line:custom-no-magic-numbers
-        const errPercentageTimes1000000 = remainder.mul(1000000).div(numerator.mul(target));
+        const errPercentageTimes1000000 = remainder.multipliedBy(1000000).div(numerator.multipliedBy(target));
         // tslint:disable-next-line:custom-no-magic-numbers
         const isError = errPercentageTimes1000000.gt(1000);
         return isError;
@@ -108,7 +108,7 @@ export class OrderValidationUtils {
     }
     private static _validateOrderNotExpiredOrThrow(expirationTimeSeconds: BigNumber): void {
         const currentUnixTimestampSec = utils.getCurrentUnixTimestampSec();
-        if (expirationTimeSeconds.lessThan(currentUnixTimestampSec)) {
+        if (expirationTimeSeconds.isLessThan(currentUnixTimestampSec)) {
             throw new Error(RevertReason.OrderUnfillable);
         }
     }
@@ -216,7 +216,7 @@ export class OrderValidationUtils {
         }
         OrderValidationUtils._validateOrderNotExpiredOrThrow(signedOrder.expirationTimeSeconds);
         const remainingTakerTokenAmount = signedOrder.takerAssetAmount.minus(filledTakerTokenAmount);
-        const desiredFillTakerTokenAmount = remainingTakerTokenAmount.lessThan(fillTakerAssetAmount)
+        const desiredFillTakerTokenAmount = remainingTakerTokenAmount.isLessThan(fillTakerAssetAmount)
             ? remainingTakerTokenAmount
             : fillTakerAssetAmount;
         try {
diff --git a/packages/order-utils/src/rate_utils.ts b/packages/order-utils/src/rate_utils.ts
index 416e00c67..dacdbd5a2 100644
--- a/packages/order-utils/src/rate_utils.ts
+++ b/packages/order-utils/src/rate_utils.ts
@@ -22,7 +22,7 @@ export const rateUtils = {
             feeRate.gte(constants.ZERO_AMOUNT),
             `Expected feeRate: ${feeRate} to be greater than or equal to 0`,
         );
-        const takerAssetAmountNeededToPayForFees = order.takerFee.mul(feeRate);
+        const takerAssetAmountNeededToPayForFees = order.takerFee.multipliedBy(feeRate);
         const totalTakerAssetAmount = takerAssetAmountNeededToPayForFees.plus(order.takerAssetAmount);
         const rate = totalTakerAssetAmount.div(order.makerAssetAmount);
         return rate;
@@ -35,9 +35,9 @@ export const rateUtils = {
      */
     getFeeAdjustedRateOfFeeOrder(feeOrder: Order): BigNumber {
         assert.doesConformToSchema('feeOrder', feeOrder, schemas.orderSchema);
-        const zrxAmountAfterFees = feeOrder.makerAssetAmount.sub(feeOrder.takerFee);
+        const zrxAmountAfterFees = feeOrder.makerAssetAmount.minus(feeOrder.takerFee);
         assert.assert(
-            zrxAmountAfterFees.greaterThan(constants.ZERO_AMOUNT),
+            zrxAmountAfterFees.isGreaterThan(constants.ZERO_AMOUNT),
             `Expected takerFee: ${JSON.stringify(feeOrder.takerFee)} to be less than makerAssetAmount: ${JSON.stringify(
                 feeOrder.makerAssetAmount,
             )}`,
diff --git a/packages/order-utils/src/remaining_fillable_calculator.ts b/packages/order-utils/src/remaining_fillable_calculator.ts
index 052eafa1d..92ffc8e80 100644
--- a/packages/order-utils/src/remaining_fillable_calculator.ts
+++ b/packages/order-utils/src/remaining_fillable_calculator.ts
@@ -39,15 +39,15 @@ export class RemainingFillableCalculator {
     private _hasSufficientFundsForFeeAndTransferAmount(): boolean {
         if (this._isTraderAssetZRX) {
             const totalZRXTransferAmountRequired = this._remainingOrderAssetAmount.plus(this._remainingOrderFeeAmount);
-            const hasSufficientFunds = this._transferrableAssetAmount.greaterThanOrEqualTo(
+            const hasSufficientFunds = this._transferrableAssetAmount.isGreaterThanOrEqualTo(
                 totalZRXTransferAmountRequired,
             );
             return hasSufficientFunds;
         } else {
-            const hasSufficientFundsForTransferAmount = this._transferrableAssetAmount.greaterThanOrEqualTo(
+            const hasSufficientFundsForTransferAmount = this._transferrableAssetAmount.isGreaterThanOrEqualTo(
                 this._remainingOrderAssetAmount,
             );
-            const hasSufficientFundsForFeeAmount = this._transferrableFeeAmount.greaterThanOrEqualTo(
+            const hasSufficientFundsForFeeAmount = this._transferrableFeeAmount.isGreaterThanOrEqualTo(
                 this._remainingOrderFeeAmount,
             );
             const hasSufficientFunds = hasSufficientFundsForTransferAmount && hasSufficientFundsForFeeAmount;
diff --git a/packages/order-utils/src/salt.ts b/packages/order-utils/src/salt.ts
index ff47ab5d2..95df66c99 100644
--- a/packages/order-utils/src/salt.ts
+++ b/packages/order-utils/src/salt.ts
@@ -13,6 +13,6 @@ export function generatePseudoRandomSalt(): BigNumber {
     // Source: https://mikemcl.github.io/bignumber.js/#random
     const randomNumber = BigNumber.random(MAX_DIGITS_IN_UNSIGNED_256_INT);
     const factor = new BigNumber(10).pow(MAX_DIGITS_IN_UNSIGNED_256_INT - 1);
-    const salt = randomNumber.times(factor).round();
+    const salt = randomNumber.times(factor).integerValue();
     return salt;
 }
diff --git a/packages/order-utils/src/utils.ts b/packages/order-utils/src/utils.ts
index 6b2261001..64195dbed 100644
--- a/packages/order-utils/src/utils.ts
+++ b/packages/order-utils/src/utils.ts
@@ -10,13 +10,13 @@ export const utils = {
     },
     getCurrentUnixTimestampSec(): BigNumber {
         const milisecondsInSecond = 1000;
-        return new BigNumber(Date.now() / milisecondsInSecond).round();
+        return new BigNumber(Date.now() / milisecondsInSecond).integerValue();
     },
     getPartialAmountFloor(numerator: BigNumber, denominator: BigNumber, target: BigNumber): BigNumber {
         const fillMakerTokenAmount = numerator
-            .mul(target)
+            .multipliedBy(target)
             .div(denominator)
-            .round(0);
+            .integerValue(0);
         return fillMakerTokenAmount;
     },
 };
diff --git a/packages/order-utils/test/remaining_fillable_calculator_test.ts b/packages/order-utils/test/remaining_fillable_calculator_test.ts
index c55a76def..affad8f1c 100644
--- a/packages/order-utils/test/remaining_fillable_calculator_test.ts
+++ b/packages/order-utils/test/remaining_fillable_calculator_test.ts
@@ -162,7 +162,7 @@ describe('RemainingFillableCalculator', () => {
                     remainingMakeAssetAmount,
                 );
                 const calculatedFillableAmount = calculator.computeRemainingFillable();
-                expect(calculatedFillableAmount.lessThanOrEqualTo(transferrableMakeAssetAmount)).to.be.true();
+                expect(calculatedFillableAmount.isLessThanOrEqualTo(transferrableMakeAssetAmount)).to.be.true();
                 expect(calculatedFillableAmount).to.be.bignumber.greaterThan(new BigNumber(0));
                 const orderToFeeRatio = signedOrder.makerAssetAmount.dividedBy(signedOrder.makerFee);
                 const calculatedFeeAmount = calculatedFillableAmount.dividedBy(orderToFeeRatio);
diff --git a/packages/order-utils/test/signature_utils_test.ts b/packages/order-utils/test/signature_utils_test.ts
index 84e5559a9..937382056 100644
--- a/packages/order-utils/test/signature_utils_test.ts
+++ b/packages/order-utils/test/signature_utils_test.ts
@@ -132,10 +132,10 @@ describe('Signature utils', () => {
         });
         it('generates salt in range [0..2^256)', () => {
             const salt = generatePseudoRandomSalt();
-            expect(salt.greaterThanOrEqualTo(0)).to.be.true();
+            expect(salt.isGreaterThanOrEqualTo(0)).to.be.true();
             // tslint:disable-next-line:custom-no-magic-numbers
             const twoPow256 = new BigNumber(2).pow(256);
-            expect(salt.lessThan(twoPow256)).to.be.true();
+            expect(salt.isLessThan(twoPow256)).to.be.true();
         });
     });
     describe('#ecSignOrderAsync', () => {
diff --git a/packages/order-watcher/src/order_watcher/expiration_watcher.ts b/packages/order-watcher/src/order_watcher/expiration_watcher.ts
index ad20a6e3f..82590efde 100644
--- a/packages/order-watcher/src/order_watcher/expiration_watcher.ts
+++ b/packages/order-watcher/src/order_watcher/expiration_watcher.ts
@@ -73,7 +73,7 @@ export class ExpirationWatcher {
                 break;
             }
             const nextOrderHashToExpire = this._orderHashByExpirationRBTree.min();
-            const hasNoExpiredOrders = this._expiration[nextOrderHashToExpire].greaterThan(
+            const hasNoExpiredOrders = this._expiration[nextOrderHashToExpire].isGreaterThan(
                 currentUnixTimestampMs.plus(this._expirationMarginMs),
             );
             const isSubscriptionActive = _.isUndefined(this._orderExpirationCheckingIntervalIdIfExists);
diff --git a/packages/order-watcher/src/utils/utils.ts b/packages/order-watcher/src/utils/utils.ts
index a7d10aaf9..9c3849ff1 100644
--- a/packages/order-watcher/src/utils/utils.ts
+++ b/packages/order-watcher/src/utils/utils.ts
@@ -3,7 +3,7 @@ import { BigNumber } from '@0x/utils';
 export const utils = {
     getCurrentUnixTimestampSec(): BigNumber {
         const milisecondsInASecond = 1000;
-        return new BigNumber(Date.now() / milisecondsInASecond).round();
+        return new BigNumber(Date.now() / milisecondsInASecond).integerValue();
     },
     getCurrentUnixTimestampMs(): BigNumber {
         return new BigNumber(Date.now());
diff --git a/packages/order-watcher/test/order_watcher_test.ts b/packages/order-watcher/test/order_watcher_test.ts
index 41dc884d5..28b564b32 100644
--- a/packages/order-watcher/test/order_watcher_test.ts
+++ b/packages/order-watcher/test/order_watcher_test.ts
@@ -317,7 +317,7 @@ describe('OrderWatcher', () => {
                     const validOrderState = orderState as OrderStateValid;
                     expect(validOrderState.orderHash).to.be.equal(orderHash);
                     const orderRelevantState = validOrderState.orderRelevantState;
-                    const remainingMakerBalance = makerBalance.sub(fillAmountInBaseUnits);
+                    const remainingMakerBalance = makerBalance.minus(fillAmountInBaseUnits);
                     const remainingFillable = fillableAmount.minus(fillAmountInBaseUnits);
                     expect(orderRelevantState.remainingFillableMakerAssetAmount).to.be.bignumber.equal(
                         remainingFillable,
@@ -434,7 +434,7 @@ describe('OrderWatcher', () => {
                     );
 
                     const remainingAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(1), decimals);
-                    const transferAmount = makerBalance.sub(remainingAmount);
+                    const transferAmount = makerBalance.minus(remainingAmount);
                     await orderWatcher.addOrderAsync(signedOrder);
 
                     const callback = callbackErrorReporter.reportNodeCallbackErrors(done)((orderState: OrderState) => {
@@ -475,7 +475,7 @@ describe('OrderWatcher', () => {
                     const remainingFeeAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(3), decimals);
 
                     const remainingTokenAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(4), decimals);
-                    const transferTokenAmount = makerFee.sub(remainingTokenAmount);
+                    const transferTokenAmount = makerFee.minus(remainingTokenAmount);
                     await orderWatcher.addOrderAsync(signedOrder);
 
                     const callback = callbackErrorReporter.reportNodeCallbackErrors(done)((orderState: OrderState) => {
diff --git a/packages/pipeline/src/utils/transformers/number_to_bigint.ts b/packages/pipeline/src/utils/transformers/number_to_bigint.ts
index 9736d7c18..8fbd52093 100644
--- a/packages/pipeline/src/utils/transformers/number_to_bigint.ts
+++ b/packages/pipeline/src/utils/transformers/number_to_bigint.ts
@@ -19,7 +19,7 @@ export class NumberToBigIntTransformer implements ValueTransformer {
 
     // tslint:disable-next-line:prefer-function-over-method
     public from(value: string): number {
-        if (new BigNumber(value).greaterThan(Number.MAX_SAFE_INTEGER)) {
+        if (new BigNumber(value).isGreaterThan(Number.MAX_SAFE_INTEGER)) {
             throw new Error(
                 `Attempted to convert PostgreSQL bigint value (${value}) to JavaScript number type but it is too big to safely convert`,
             );
diff --git a/packages/testnet-faucets/src/ts/dispense_asset_tasks.ts b/packages/testnet-faucets/src/ts/dispense_asset_tasks.ts
index 32f5cb623..58caeeeaa 100644
--- a/packages/testnet-faucets/src/ts/dispense_asset_tasks.ts
+++ b/packages/testnet-faucets/src/ts/dispense_asset_tasks.ts
@@ -19,7 +19,7 @@ export const dispenseAssetTasks = {
             logUtils.log(`Processing ETH ${recipientAddress}`);
             const userBalance = await web3Wrapper.getBalanceInWeiAsync(recipientAddress);
             const maxAmountInWei = Web3Wrapper.toWei(new BigNumber(DISPENSE_MAX_AMOUNT_ETHER));
-            if (userBalance.greaterThanOrEqualTo(maxAmountInWei)) {
+            if (userBalance.isGreaterThanOrEqualTo(maxAmountInWei)) {
                 logUtils.log(
                     `User exceeded ETH balance maximum (${maxAmountInWei}) ${recipientAddress} ${userBalance} `,
                 );
@@ -55,7 +55,7 @@ export const dispenseAssetTasks = {
                 new BigNumber(DISPENSE_MAX_AMOUNT_TOKEN),
                 tokenIfExists.decimals,
             );
-            if (userBalanceBaseUnits.greaterThanOrEqualTo(maxAmountBaseUnits)) {
+            if (userBalanceBaseUnits.isGreaterThanOrEqualTo(maxAmountBaseUnits)) {
                 logUtils.log(
                     `User exceeded token balance maximum (${maxAmountBaseUnits}) ${recipientAddress} ${userBalanceBaseUnits} `,
                 );
diff --git a/packages/testnet-faucets/src/ts/handler.ts b/packages/testnet-faucets/src/ts/handler.ts
index 8f642d4b0..54387749f 100644
--- a/packages/testnet-faucets/src/ts/handler.ts
+++ b/packages/testnet-faucets/src/ts/handler.ts
@@ -179,7 +179,7 @@ export class Handler {
             feeRecipientAddress: NULL_ADDRESS,
             senderAddress: NULL_ADDRESS,
             // tslint:disable-next-line:custom-no-magic-numbers
-            expirationTimeSeconds: new BigNumber(Date.now() + FIVE_DAYS_IN_MS).div(1000).floor(),
+            expirationTimeSeconds: new BigNumber(Date.now() + FIVE_DAYS_IN_MS).div(1000).integerValue(BigNumber.ROUND_FLOOR),
         };
         const orderHash = orderHashUtils.getOrderHashHex(order);
         const signature = await signatureUtils.ecSignHashAsync(
diff --git a/packages/types/package.json b/packages/types/package.json
index 2fea809bc..440f05423 100644
--- a/packages/types/package.json
+++ b/packages/types/package.json
@@ -31,7 +31,7 @@
     },
     "dependencies": {
         "@types/node": "*",
-        "bignumber.js": "~4.1.0",
+        "bignumber.js": "~8.0.2",
         "ethereum-types": "^1.1.6"
     },
     "publishConfig": {
diff --git a/packages/typescript-typings/package.json b/packages/typescript-typings/package.json
index 6640760e4..01cab8c63 100644
--- a/packages/typescript-typings/package.json
+++ b/packages/typescript-typings/package.json
@@ -26,7 +26,7 @@
     "dependencies": {
         "@types/bn.js": "^4.11.0",
         "@types/react": "*",
-        "bignumber.js": "~4.1.0",
+        "bignumber.js": "~8.0.2",
         "ethereum-types": "^1.1.6",
         "popper.js": "1.14.3"
     },
diff --git a/packages/utils/package.json b/packages/utils/package.json
index 315f5a08f..3b16550a5 100644
--- a/packages/utils/package.json
+++ b/packages/utils/package.json
@@ -48,7 +48,7 @@
         "@0x/typescript-typings": "^3.0.8",
         "@types/node": "*",
         "abortcontroller-polyfill": "^1.1.9",
-        "bignumber.js": "~4.1.0",
+        "bignumber.js": "~8.0.2",
         "chalk": "^2.4.1",
         "detect-node": "2.0.3",
         "ethereum-types": "^1.1.6",
diff --git a/packages/utils/src/abi_encoder/evm_data_types/bool.ts b/packages/utils/src/abi_encoder/evm_data_types/bool.ts
index 7f91f34e6..23298bc88 100644
--- a/packages/utils/src/abi_encoder/evm_data_types/bool.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types/bool.ts
@@ -37,11 +37,11 @@ export class BoolDataType extends AbstractBlobDataType {
         const valueBuf = calldata.popWord();
         const valueHex = ethUtil.bufferToHex(valueBuf);
         const valueNumber = new BigNumber(valueHex, constants.HEX_BASE);
-        if (!(valueNumber.equals(0) || valueNumber.equals(1))) {
+        if (!(valueNumber.isEqualTo(0) || valueNumber.isEqualTo(1))) {
             throw new Error(`Failed to decode boolean. Expected 0x0 or 0x1, got ${valueHex}`);
         }
         /* tslint:disable boolean-naming */
-        const value: boolean = !valueNumber.equals(0);
+        const value: boolean = !valueNumber.isEqualTo(0);
         /* tslint:enable boolean-naming */
         return value;
     }
diff --git a/packages/utils/src/abi_encoder/evm_data_types/int.ts b/packages/utils/src/abi_encoder/evm_data_types/int.ts
index 8d98e195b..b7e0d9f4e 100644
--- a/packages/utils/src/abi_encoder/evm_data_types/int.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types/int.ts
@@ -38,8 +38,8 @@ export class IntDataType extends AbstractBlobDataType {
             throw new Error(`Tried to instantiate Int with bad input: ${dataItem}`);
         }
         this._width = IntDataType._decodeWidthFromType(dataItem.type);
-        this._minValue = new BigNumber(2).toPower(this._width - 1).times(-1);
-        this._maxValue = new BigNumber(2).toPower(this._width - 1).sub(1);
+        this._minValue = new BigNumber(2).exponentiatedBy(this._width - 1).times(-1);
+        this._maxValue = new BigNumber(2).exponentiatedBy(this._width - 1).minus(1);
     }
 
     public encodeValue(value: BigNumber | string | number): Buffer {
diff --git a/packages/utils/src/abi_encoder/evm_data_types/uint.ts b/packages/utils/src/abi_encoder/evm_data_types/uint.ts
index 8e382e8dc..a82aa789e 100644
--- a/packages/utils/src/abi_encoder/evm_data_types/uint.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types/uint.ts
@@ -38,7 +38,7 @@ export class UIntDataType extends AbstractBlobDataType {
             throw new Error(`Tried to instantiate UInt with bad input: ${dataItem}`);
         }
         this._width = UIntDataType._decodeWidthFromType(dataItem.type);
-        this._maxValue = new BigNumber(2).toPower(this._width).sub(1);
+        this._maxValue = new BigNumber(2).exponentiatedBy(this._width).minus(1);
     }
 
     public encodeValue(value: BigNumber | string | number): Buffer {
diff --git a/packages/utils/src/abi_encoder/utils/math.ts b/packages/utils/src/abi_encoder/utils/math.ts
index d84983c5b..b2fa5fe7d 100644
--- a/packages/utils/src/abi_encoder/utils/math.ts
+++ b/packages/utils/src/abi_encoder/utils/math.ts
@@ -10,9 +10,9 @@ function sanityCheckBigNumberRange(
     maxValue: BigNumber,
 ): void {
     const value = new BigNumber(value_, 10);
-    if (value.greaterThan(maxValue)) {
+    if (value.isGreaterThan(maxValue)) {
         throw new Error(`Tried to assign value of ${value}, which exceeds max value of ${maxValue}`);
-    } else if (value.lessThan(minValue)) {
+    } else if (value.isLessThan(minValue)) {
         throw new Error(`Tried to assign value of ${value}, which exceeds min value of ${minValue}`);
     }
 }
@@ -30,7 +30,7 @@ function bigNumberToPaddedBuffer(value: BigNumber): Buffer {
 export function encodeNumericValue(value_: BigNumber | string | number): Buffer {
     const value = new BigNumber(value_, 10);
     // Case 1/2: value is non-negative
-    if (value.greaterThanOrEqualTo(0)) {
+    if (value.isGreaterThanOrEqualTo(0)) {
         const encodedPositiveValue = bigNumberToPaddedBuffer(value);
         return encodedPositiveValue;
     }
@@ -74,7 +74,7 @@ export function decodeNumericValue(encodedValue: Buffer, minValue: BigNumber): B
     const valueHex = ethUtil.bufferToHex(encodedValue);
     // Case 1/3: value is definitely non-negative because of numeric boundaries
     const value = new BigNumber(valueHex, constants.HEX_BASE);
-    if (!minValue.lessThan(0)) {
+    if (!minValue.isLessThan(0)) {
         return value;
     }
     // Case 2/3: value is non-negative because there is no leading 1 (encoded as two's-complement)
diff --git a/packages/web3-wrapper/src/utils.ts b/packages/web3-wrapper/src/utils.ts
index c68587632..1b67518b1 100644
--- a/packages/web3-wrapper/src/utils.ts
+++ b/packages/web3-wrapper/src/utils.ts
@@ -37,7 +37,7 @@ export const utils = {
         const hexBase = 16;
         const valueHex = valueBigNumber.toString(hexBase);
 
-        return valueBigNumber.lessThan(0) ? `-0x${valueHex.substr(1)}` : `0x${valueHex}`;
+        return valueBigNumber.isLessThan(0) ? `-0x${valueHex.substr(1)}` : `0x${valueHex}`;
     },
     numberToHex(value: number): string {
         if (!isFinite(value) && !utils.isHexStrict(value)) {
diff --git a/packages/website/ts/blockchain.ts b/packages/website/ts/blockchain.ts
index 37f746f7c..ea5a59340 100644
--- a/packages/website/ts/blockchain.ts
+++ b/packages/website/ts/blockchain.ts
@@ -944,7 +944,7 @@ export class Blockchain {
         try {
             const gasInfo = await backendClient.getGasInfoAsync();
             const gasPriceInGwei = new BigNumber(gasInfo.fast / 10);
-            const gasPriceInWei = gasPriceInGwei.mul(1000000000);
+            const gasPriceInWei = gasPriceInGwei.multipliedBy(1000000000);
             this._defaultGasPrice = gasPriceInWei;
         } catch (err) {
             return;
diff --git a/packages/website/ts/components/fill_order.tsx b/packages/website/ts/components/fill_order.tsx
index 7fee8c4df..95a3671c4 100644
--- a/packages/website/ts/components/fill_order.tsx
+++ b/packages/website/ts/components/fill_order.tsx
@@ -205,7 +205,7 @@ export class FillOrder extends React.Component<FillOrderProps, FillOrderState> {
             amount: orderMakerAmount
                 .times(takerAssetToken.amount)
                 .div(orderTakerAmount)
-                .floor(),
+                .integerValue(BigNumber.ROUND_FLOOR),
             symbol: makerToken.symbol,
         };
         const fillAssetToken = {
@@ -219,7 +219,7 @@ export class FillOrder extends React.Component<FillOrderProps, FillOrderState> {
             const orderReceiveAmountBigNumber = orderMakerAmount
                 .times(this.props.orderFillAmount)
                 .dividedBy(orderTakerAmount)
-                .floor();
+                .integerValue(BigNumber.ROUND_FLOOR);
             orderReceiveAmount = this._formatCurrencyAmount(orderReceiveAmountBigNumber, makerToken.decimals);
         }
         const isUserMaker =
diff --git a/packages/website/ts/utils/utils.ts b/packages/website/ts/utils/utils.ts
index 890f1553a..e84f9d0cc 100644
--- a/packages/website/ts/utils/utils.ts
+++ b/packages/website/ts/utils/utils.ts
@@ -394,7 +394,7 @@ export const utils = {
     },
     getUsdValueFormattedAmount(amount: BigNumber, decimals: number, price: BigNumber): string {
         const unitAmount = Web3Wrapper.toUnitAmount(amount, decimals);
-        const value = unitAmount.mul(price);
+        const value = unitAmount.multipliedBy(price);
         return utils.format(value, constants.NUMERAL_USD_FORMAT);
     },
     openUrl(url: string): void {