(a+n)-n

Answer: a

Reason:

• (a + n) − n = (a + n) + (−n)
• By associativity: a + (n + (−n)) = a + 0
• Since n + (−n) = 0, we get a + 0 = a

This holds in any context with addition, subtraction (as adding inverses), and a zero identity (e.g., real numbers, vectors, matrices, any abelian group). If you plug in numbers as a check: (5 + 3) − 3 = 8 − 3 = 5.