Dividing Fractions
Dividing fractions challenges even confident 6th graders, but mastering the "keep, flip, multiply" rule transforms this complex operation into a straightforward process. When students understand that dividing by 3/4 is the same as multiplying by 4/3, they gain access to solving real-world problems involving recipes, measurements, and fair sharing scenarios.
Why it matters
Division of fractions appears constantly in practical situations that students encounter. A baker dividing 23 cup of flour into portions of 16 cup each needs to calculate 23 ÷ 16 = 4 portions. Construction workers splitting a 34 inch board into 18 inch strips perform 34 ÷ 18 = 6 strips. Students planning a fundraiser must determine how many $0.25 items they can buy with $3.75, solving 3.75 ÷ 0.25 = 15 items. These calculations build number sense and prepare students for algebra, where dividing by fractions becomes essential for solving complex equations. The CCSS 6.NS standards emphasize this skill because it bridges elementary fraction understanding with advanced mathematical reasoning, making students confident problem-solvers across multiple contexts.
How to solve dividing fractions
Dividing Fractions
- Keep the first fraction.
- Flip the second fraction (reciprocal).
- Multiply. Simplify.
Example: 23 ÷ 45 → 23 × 54 = 1012 = 56.
Worked examples
You have 13 of a pizza. You share it equally among friends who each get 12. How many shares?
Answer: 23
- Invert and multiply → 1/3 x 2/1 = 2/3 — Sharing equally means dividing. Flip the second fraction, then multiply across.
- Simplify → 2/3 — Reduce to lowest terms.
- Verify → 2/3 ✓ — Answer.
A rope is 16 m long. You cut it into pieces 12 m each. How many pieces?
Answer: 13
- Invert and multiply → 1/6 x 2/1 = 2/6 — Cutting into equal pieces is division. Flip the second fraction, then multiply across.
- Simplify → 1/3 — Reduce to lowest terms.
- Verify → 1/3 ✓ — Answer.
13 / 35 = _______
Answer: 59
- Invert and multiply → 1/3 x 5/3 = 5/9 — Flip the second fraction, then multiply across.
- Simplify → 5/9 — Reduce to lowest terms.
- Verify → 5/9 ✓ — Answer.
Common mistakes
- Students often divide straight across, calculating 1/2 ÷ 1/3 as 1/6 instead of the correct answer 3/2, forgetting to flip the second fraction before multiplying.
- Many students flip the wrong fraction, computing 2/3 ÷ 1/4 as 1/4 × 2/3 = 2/12 instead of 2/3 × 4/1 = 8/3, confusing which fraction becomes the reciprocal.
- Students frequently skip simplification, leaving answers like 6/4 instead of reducing to 3/2, missing the final step of expressing results in lowest terms.
- When working with mixed numbers like 2 1/3 ÷ 1/2, students often divide only the fraction parts, getting 1/6 instead of converting to improper fractions first: 7/3 ÷ 1/2 = 14/3.