diff --git a/contracts/fees/TokenDistributor.sol b/contracts/fees/TokenDistributor.sol
index a36a707c..6591ddc6 100644
--- a/contracts/fees/TokenDistributor.sol
+++ b/contracts/fees/TokenDistributor.sol
@@ -9,6 +9,7 @@ import '@openzeppelin/contracts/utils/ReentrancyGuard.sol';
 import '../libraries/openzeppelin-upgradeability/VersionedInitializable.sol';
 import '../interfaces/IExchangeAdapter.sol';
 import '../libraries/UniversalERC20.sol';
+import {PercentageMath} from '../libraries/PercentageMath.sol';
 
 /// @title TokenDistributor
 /// @author Aave
@@ -22,6 +23,7 @@ import '../libraries/UniversalERC20.sol';
 ///    and burn it (sending to address(0) the tokenToBurn)
 contract TokenDistributor is ReentrancyGuard, VersionedInitializable {
   using SafeMath for uint256;
+  using PercentageMath for uint256;
   using UniversalERC20 for IERC20;
 
   struct Distribution {
@@ -126,10 +128,9 @@ contract TokenDistributor is ReentrancyGuard, VersionedInitializable {
     public
   {
     for (uint256 i = 0; i < _tokens.length; i++) {
-      uint256 _amountToDistribute = _tokens[i]
-        .universalBalanceOf(address(this))
-        .mul(_percentages[i])
-        .div(100);
+      uint256 _amountToDistribute = _tokens[i].universalBalanceOf(address(this)).percentMul(
+        _percentages[i]
+      );
 
       if (_amountToDistribute <= 0) {
         continue;
diff --git a/contracts/lendingpool/LendingPoolLiquidationManager.sol b/contracts/lendingpool/LendingPoolLiquidationManager.sol
index c54aee6f..c7c614dd 100644
--- a/contracts/lendingpool/LendingPoolLiquidationManager.sol
+++ b/contracts/lendingpool/LendingPoolLiquidationManager.sol
@@ -20,6 +20,7 @@ import '../libraries/UserLogic.sol';
 import '../libraries/ReserveLogic.sol';
 import '../libraries/UniversalERC20.sol';
 import '../libraries/ReserveConfiguration.sol';
+import {PercentageMath} from '../libraries/PercentageMath.sol';
 
 /**
  * @title LendingPoolLiquidationManager contract
@@ -30,6 +31,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
   using UniversalERC20 for IERC20;
   using SafeMath for uint256;
   using WadRayMath for uint256;
+  using PercentageMath for uint256;
   using Address for address;
   using ReserveLogic for ReserveLogic.ReserveData;
   using UserLogic for UserLogic.UserReserveData;
@@ -177,11 +179,9 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
     }
 
     //all clear - calculate the max principal amount that can be liquidated
-    vars.maxPrincipalAmountToLiquidate = vars
-      .userStableDebt
-      .add(vars.userVariableDebt)
-      .mul(LIQUIDATION_CLOSE_FACTOR_PERCENT)
-      .div(100);
+    vars.maxPrincipalAmountToLiquidate = vars.userStableDebt.add(vars.userVariableDebt).percentMul(
+      LIQUIDATION_CLOSE_FACTOR_PERCENT
+    );
 
     vars.actualAmountToLiquidate = _purchaseAmount > vars.maxPrincipalAmountToLiquidate
       ? vars.maxPrincipalAmountToLiquidate
@@ -331,8 +331,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
       .mul(_purchaseAmount)
       .mul(10**vars.collateralDecimals)
       .div(vars.collateralPrice.mul(10**vars.principalDecimals))
-      .mul(vars.liquidationBonus)
-      .div(100);
+      .percentMul(vars.liquidationBonus);
 
     if (vars.maxAmountCollateralToLiquidate > _userCollateralBalance) {
       collateralAmount = _userCollateralBalance;
@@ -341,8 +340,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
         .mul(collateralAmount)
         .mul(10**vars.principalDecimals)
         .div(vars.principalCurrencyPrice.mul(10**vars.collateralDecimals))
-        .mul(100)
-        .div(vars.liquidationBonus);
+        .percentDiv(vars.liquidationBonus);
     } else {
       collateralAmount = vars.maxAmountCollateralToLiquidate;
       principalAmountNeeded = _purchaseAmount;
diff --git a/contracts/libraries/GenericLogic.sol b/contracts/libraries/GenericLogic.sol
index e019d466..927670bd 100644
--- a/contracts/libraries/GenericLogic.sol
+++ b/contracts/libraries/GenericLogic.sol
@@ -8,7 +8,7 @@ import {ReserveLogic} from './ReserveLogic.sol';
 import {ReserveConfiguration} from './ReserveConfiguration.sol';
 import {UserLogic} from './UserLogic.sol';
 import {WadRayMath} from './WadRayMath.sol';
-
+import {PercentageMath} from './PercentageMath.sol';
 import '../interfaces/IPriceOracleGetter.sol';
 import {IFeeProvider} from '../interfaces/IFeeProvider.sol';
 import '@nomiclabs/buidler/console.sol';
@@ -23,6 +23,7 @@ library GenericLogic {
   using UserLogic for UserLogic.UserReserveData;
   using SafeMath for uint256;
   using WadRayMath for uint256;
+  using PercentageMath for uint256;
   using ReserveConfiguration for ReserveConfiguration.Map;
 
   uint256 public constant HEALTH_FACTOR_LIQUIDATION_THRESHOLD = 1e18;
@@ -237,7 +238,7 @@ library GenericLogic {
   ) internal view returns (uint256) {
     if (borrowBalanceETH == 0) return uint256(-1);
 
-    return (collateralBalanceETH.mul(liquidationThreshold).div(100)).wadDiv(borrowBalanceETH);
+    return (collateralBalanceETH.percentMul(liquidationThreshold)).wadDiv(borrowBalanceETH);
   }
 
   /**
@@ -254,7 +255,7 @@ library GenericLogic {
     uint256 borrowBalanceETH,
     uint256 ltv
   ) external view returns (uint256) {
-    uint256 availableBorrowsETH = collateralBalanceETH.mul(ltv).div(100); //ltv is in percentage
+    uint256 availableBorrowsETH = collateralBalanceETH.percentMul(ltv); //ltv is in percentage
 
     if (availableBorrowsETH < borrowBalanceETH) {
       return 0;
diff --git a/contracts/libraries/PercentageMath.sol b/contracts/libraries/PercentageMath.sol
index 7ce7c076..e85769b2 100644
--- a/contracts/libraries/PercentageMath.sol
+++ b/contracts/libraries/PercentageMath.sol
@@ -23,6 +23,6 @@ library PercentageMath {
   function percentDiv(uint256 value, uint256 percentage) internal pure returns (uint256) {
     uint256 halfPercentage = percentage / 2;
 
-    return halfPercentage.add(value.mul(PERCENTAGE_FACTOR)).div(halfPercentage);
+    return halfPercentage.add(value.mul(PERCENTAGE_FACTOR)).div(percentage);
   }
 }
diff --git a/contracts/libraries/ValidationLogic.sol b/contracts/libraries/ValidationLogic.sol
index 8e4a6a12..8f299ca6 100644
--- a/contracts/libraries/ValidationLogic.sol
+++ b/contracts/libraries/ValidationLogic.sol
@@ -8,6 +8,7 @@ import {ReserveLogic} from './ReserveLogic.sol';
 import {UserLogic} from './UserLogic.sol';
 import {GenericLogic} from './GenericLogic.sol';
 import {WadRayMath} from './WadRayMath.sol';
+import {PercentageMath} from './PercentageMath.sol';
 import {UniversalERC20} from './UniversalERC20.sol';
 import {ReserveConfiguration} from './ReserveConfiguration.sol';
 import {IPriceOracleGetter} from '../interfaces/IPriceOracleGetter.sol';
@@ -24,6 +25,7 @@ library ValidationLogic {
   using UserLogic for UserLogic.UserReserveData;
   using SafeMath for uint256;
   using WadRayMath for uint256;
+  using PercentageMath for uint256;
   using UniversalERC20 for IERC20;
   using ReserveConfiguration for ReserveConfiguration.Map;
 
@@ -161,7 +163,7 @@ library ValidationLogic {
     require(vars.healthFactor > GenericLogic.HEALTH_FACTOR_LIQUIDATION_THRESHOLD, '8');
 
     //add the current already borrowed amount to the amount requested to calculate the total collateral needed.
-    vars.amountOfCollateralNeededETH = vars.userBorrowBalanceETH.add(_amountInETH).mul(100).div(
+    vars.amountOfCollateralNeededETH = vars.userBorrowBalanceETH.add(_amountInETH).percentDiv(
       vars.currentLtv
     ); //LTV is calculated in percentage
 
@@ -193,7 +195,7 @@ library ValidationLogic {
 
       //calculate the max available loan size in stable rate mode as a percentage of the
       //available liquidity
-      uint256 maxLoanSizeStable = vars.availableLiquidity.mul(_maxStableLoanPercent).div(100);
+      uint256 maxLoanSizeStable = vars.availableLiquidity.percentMul(_maxStableLoanPercent);
 
       require(_amount <= maxLoanSizeStable, '13');
     }