Use the inputs in each method to compute a result that will still work when the numbers change. These tasks revisit text concatenation, remaining counts, long values, complete groups and fractional averages. Each task gives its own rule, so read whether it asks for a group count, a remainder or a boolean permission before choosing an operator.
The visible example is one observation. Hidden checks include boundaries and different values, which is why returning its answer as a constant will fail. Check your operand types before an operation that can overflow or lose a fraction. For logical rules, test both an accepted case and a case where just one required condition is false. You can use any implementation that follows the contract.