```\n uint256 deltaExchangeRateMantissa = uint256(exchangeRateMantissa).sub(userState.lastExchangeRateMantissa);\n    uint128 newTokens = FixedPoint.multiplyUintByMantissa(userMeasureBalance, deltaExchangeRateMantissa).toUint128();\n    userStates[user] = UserState({\n      lastExchangeRateMantissa: exchangeRateMantissa,\n      balance: uint256(userState.balance).add(newTokens).toUint128()\n    });\n```\n