For my program, I am trying to assist the user, and reduce his or her work load.

There are four input numbers. There is also an indeterminate amount of numbers they can be applied too.

For example, they four input numbers could be {4,7,3,2} and the numbers they can be applied to are {4,9,23}

The result should be: 4 (input) was applied to 4, leaving the sets looking like: {0,7,3,2} and then 7,2 (input) are applied to 9 leaving the sets looking like: {0,0,3,0} and {0,0,23} and because 3 or any other permutation including 3 does not match 23, 3 remains.

How would I do this?