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).
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
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.