Two operations that undo each other are called inverse operations. Examples are addition and subtraction, or multiplication and division.
Inverse operations are opposite operations that undo each other. Addition and subtraction are inverse operations. Multiplication and division are inverse operations.
Assuming each digit only once: 65432 (and no further mathematical operations).
the Inverse Operation. This answer is relative to math, and operations.
Gottfried Leibniz and Sir Isaac Newton