7th Grade · The Number System
Difference
7.NS.A.1c
Definition
The result of subtraction. To subtract an integer, add its additive inverse (opposite): a - b = a + (-b).
Examples
- 7 - (-3) = 7 + 3 = 10.
- (-5) - 2 = (-5) + (-2) = -7, and (-4) - (-6) = (-4) + 6 = 2.
Key rule
Never subtract integers directly — rewrite as adding the opposite (KCC).
Memory hook
Subtract = add the opposite.