In mathematics, what is the additive inverse of 1?

• A. 1
• B. 0
• C. -1
• D. -2

Answer: (C)

To find the additive inverse, look for the number that makes the sum zero when added to the given number. For 1, the opposite is -1 because 1 + (-1) = 0. That’s why -1 is the additive inverse. The other options don’t cancel the 1 to zero: 1 + 1 = 2, 1 + 0 = 1, and 1 + (-2) = -1. This concept reflects opposite numbers on the number line — every number has a partner that brings the total to zero under addition.