GCSE-ready- Home
- Lessons
- KS3 Mathematics
- Multiplying and dividing fractions
Multiplying and dividing fractions
🎬 The doodle video for this lesson is coming soon. Subscribe on YouTube to see it first.
Multiplying and dividing fractions is quicker than adding them: you do not need a common denominator.
Multiplying
Multiply the numerators, multiply the denominators, then simplify.
23 × 35 = 615 = 25
You can cancel common factors first to keep the numbers small.
23 × 35 = 615 = 25
You can cancel common factors first to keep the numbers small.
Dividing
Keep the first fraction, change ÷ to ×, flip the second fraction (use its reciprocal).
34 ÷ 12 = 34 × 21 = 64 = 32
Dividing by a fraction less than 1 makes the answer bigger.
34 ÷ 12 = 34 × 21 = 64 = 32
Dividing by a fraction less than 1 makes the answer bigger.
Mixed numbers and negatives
Change mixed numbers to improper fractions first: 212 × 113 = 52 × 43 = 206 = 103.
The sign rules still apply: −12 × 34 = −38.
The sign rules still apply: −12 × 34 = −38.
Work out 212 ÷ 34.
- Improper fraction: 52 ÷ 34
- Flip and multiply: 52 × 43 = 206
- Simplify: 103 = 313
Answer: 313
To multiply, multiply tops and bottoms. To divide, flip the second fraction and multiply. Turn mixed numbers into improper fractions first.
Check you have got it
Answer 7 quick questions with instant marking. If you get one wrong, GCSE-ready shows you why and gives you another go. It is free, and you do not need an account.