LEARN · PRACTISE · DISCOVER

Subtract Mentally with Smart Steps

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

Subtract mentally by bridging through a ten, adjusting nearby numbers, or counting up to find a difference.

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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.

1Start at the smaller number

For 67 − 48, count the distance from 48 to 67.

2Reach a friendly fifty

48 to 50 is a jump of 2.

3Add the jumps

50 to 67 is 17 more. The difference is 2 + 17 = 19.

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. 67 − 48 equals… 29 19 21

2. For 63 − 19, subtract 20 to get 43. What next? Add 1 back Subtract 1 more Add 20

3. To solve 52 − 8 through fifty, split 8 into… 4 and 4 only 2 and 8 2 and 6

Read the answer explanations

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