7th Grade · The Number System
KCF
7.NS.A.2c
Definition
A method for dividing fractions: Keep the first fraction, Change division to multiplication, Flip the second fraction (its reciprocal). Then simplify.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- 3/4 ÷ 2/5 = 3/4 × 5/2 = 15/8.
- 2/5 becomes 5/2 (its reciprocal) while 3/4 stays the same.
Key rule
KCF only works for division; for multiplication, just multiply across.
Memory hook
Keep - Change - Flip.