Subtraction means adding the opposite: a − b is the same as a + (−b). Once rewritten, the usual integer-addition rules apply, so you never need a separate “subtraction” procedure.

Steps

1. Rewrite a − b as a + (−b).
2. Apply the same-sign / different-sign addition rules to the rewritten sum.
3. Confirm the result with a quick number-line check if the signs feel confusing.