Grade 4 · Maths · Lessons
Same amount, more pieces
🍕pizza✂️cut🟰equal✖️times
Same amount.The big ideaCut every part into smaller parts and the amount stays the same. Multiply the top and the bottom.
How it works
Cut every part into smaller parts and the amount stays the same.
Multiply the top and the bottom by the same number.
2/3 = 4/6 because each third was cut into 2.
Example 1: How many cuts?
- 2/3 = 4/6: each part was cut into how many?
- 2/3 becomes 4/6.
- 2 × 2 = 4 and 3 × 2 = 6, so each part was cut into 2.
- So the answer is 2.
Example 2: Find the bottom
- Cut each part into 2: 2/5 = 4/?
- Cut each part of 2/5 into 2.
- 5 × 2 = 10, so the bottom is 10.
- So the answer is 10.
Example 3: Find the top
- Cut each part into 3: 1/2 = ?/6
- Cut each part of 1/2 into 3.
- 1 × 3 = 3, so the top is 3.
- So the answer is 3.
Words to know
- equivalent fractions
- Fractions that name the same amount.
- cut
- To split each part into smaller equal parts.
Watch out
- Multiply the top and the bottom by the same number.
- The amount doesn't change, only the size of the pieces.
- Don't just add to the top and bottom.
Try it
- 4/5 = 8/10: each part was cut into how many?
- 1/6 = 2/12: each part was cut into how many?
- 1/2 = 5/10: each part was cut into how many?
Answers: 1. 2 · 2. 2 · 3. 5
For grown-upsFold a paper strip into halves, then fourths, then eighths and see the same amount shaded.