7th Grade · The Number System
KCC
7.NS.A.1d
Definition
A method for subtracting integers: Keep the first number, Change subtraction to addition, Change the sign of the second number. Works for all integer subtraction.
Examples
- (-3) - (-5) = (-3) + (+5) = +2.
- 7 - 9 = 7 + (-9) = -2, and -4 - (-6) = -4 + 6 = 2.
Key rule
KCC turns every subtraction into an addition.
Memory hook
Keep - Change - Change.