5th Grade · Number & Operations—Fractions
Common Denominator
5.NF.A.1
Definition
A shared denominator that lets fractions be added or subtracted.
Examples
- 1/3 becomes 4/12, and 3/4 becomes 9/12 — both now use 12.
- 1/2 becomes 3/6, and 1/3 becomes 2/6 — both now use 6.
Key rule
Use a common denominator to add or subtract fractions with different bottoms.
Memory hook
Same bottom number, so parts can combine.