LEARN · PRACTISE · DISCOVER

Use Doubling and Halving

Read at your own pace. Try the practice, then continue your course.

Use doubles, near doubles, and even-number halves to solve calculations efficiently and check related facts.

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THE CURIOSI · EXPLORE & TRY

Explore the model, then test your understanding. Select each numbered stop to discover its role.

Strategy model: follow the labelled quantities and explain each change. Number-line jumps are schematic.

1One equal part

Each half of 54 is 27.

2The other equal part

Equal halves must have the same value, so the second part is also 27.

3Double or halve

27 + 27 = 54 checks that half of 54 is 27.

Choose a strategy you can explain. Check the numbers and include units where needed.

Choose one answer for each question, then check. Practice results stay on this page and do not change course completion.

1. Use a near double: 18 + 19 equals… 37 36 38

2. Half of 86 is… 48 46 43

3. Which checks that half of 72 is 36? 72 + 72 = 36 36 + 36 = 72 36 + 2 = 72

Read the answer explanations

Focus on understanding before speed. Use paper, counters or a spoken explanation whenever they help you keep track.