Grade 6 · Number · Fraction and Decimal Operations
Choose a Unit Before Operating
Operations work when the units make sense. Fractions need common-sized parts for addition, while multiplication and division describe scaling or grouping.
The big idea
The operation and the unit must agree
To add 2/3 and 1/4, rename both fractions in twelfths. To divide 3 by 1/4, ask how many one-fourths fit into three wholes.
Work it through
Solve 2/3 + 1/4 and 3 ÷ 1/4
- 1. Use a common denominator: 2/3 = 8/12 and 1/4 = 3/12.
- 2. Add like units: 8/12 + 3/12 = 11/12.
- 3. Three wholes contain twelve fourths.
- 4. So 3 ÷ 1/4 = 12; check that 12 × 1/4 = 3.