Divide before multiply

exploit.md

In Utils.sol we have the following method

    function calcLiquidityUnits(uint b, uint B, uint t, uint T, uint P) external view returns (uint){
        if(P == 0){
            return b;
        } else {
            // units = ((P (t B + T b))/(2 T B)) * slipAdjustment
            // P * (part1 + part2) / (part3) * slipAdjustment
            uint slipAdjustment = getSlipAdustment(b, B, t, T);
            uint part1 = (t * B);
            uint part2 = (T * b);
            uint part3 = (T * B) * 2;
            uint _units = (((P * part1) + part2) / part3);
            return (_units * slipAdjustment) / one;  // Divide by 10**18
        }
    }

If we just focus in the last two lines. We can see that we are running a division before a multiplication.

    uint _units = (((P * part1) + part2) / part3);
    return (_units * slipAdjustment) / one;  // Divide by 10**18

Here we can see to examples of the importance of first multiple and then divide

   uint _units = (((1 * 3) + 2) / 10);  // _units = 0;
   return (0 * 100) / 1                 //  we return 0

   uint _units = ((1 * 3) + 2);         // _units = 5;
   return (5 * 100) / (1 * 10)          //  we return 50;

Solidity integer division might truncate. As a result, performing multiplication before division can sometimes avoid loss of precision.