Check Overflow

Extra caution should be exercised when performing addition, subtraction, or division operations. For instance, it's important to verify that an overflow hasn't occurred in cases where it could potentially happen.

Avoid:

contract AvoidContract {
    function addinGtWithoutChecking(gtUint16 lhs, gtUint16 rhs) public {
        gtUint16 addResult = MpcCore.add(lhs, rhs);
        return addResult;
    }
}

Do : Check that the result is greater than one of the operands, return zero for example on overflow

contract AvoidContract {
    function addinGtReturnZeroOnOverFlow(gtUint16 lhs, gtUint16 rhs) public {
        gtUint16 tempAddResult = MpcCore.add(lhs, rhs);
        gtBool isOverflowed = MpcCore.lt(tempAddResult , lhs);
        gtUint16 gtZero = MpcCore.setPublic16(0)
        addResult = MpcCore.mux(isOverflow, gtZero, tempAddResult);
        return addResult;
    }
}

You may also use the checkedAdd, checkedSub and checkedMul operands, which cause the transaction to revert on overflow/underflow.