Show Your Working: Subtraction with Regrouping

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Learn and practise

WALT: We are learning to subtract a one-digit number from a two-digit number by regrouping a ten, and show our working.

Regrouping means renaming one ten as 10 ones.

Worked example: 42 − 7

42 has 4 tens and 2 ones. We cannot take 7 ones from 2 ones, so rename 1 ten as 10 ones. Now there are 3 tens and 12 ones.

12 − 7 = 5 ones, and 3 tens remain. Therefore, 42 − 7 = 35.

Regrouping record: 4 tens 2 ones → 3 tens 12 ones

Answer: 3 tens 5 ones = 35

Show your working for every question. You may use crossing out and renaming.

1. 42 − 7 = ______

2. 51 − 6 = ______

3. 63 − 8 = ______

4. 70 − 4 = ______

5. 84 − 9 = ______

6. 92 − 7 = ______

Apply your thinking

7. 36 − 8 = ______

8. 75 − 9 = ______

9. Maia has 43 stickers. She gives 6 stickers to a friend. How many stickers does she have left?

10. A bus has 62 passengers. Eight passengers get off. How many passengers are still on the bus?

11. There are 81 books on a shelf. Seven books are borrowed. How many books are left?

12. Challenge: Solve 54 − 8 in two different ways. Explain which method you prefer.

Self-check using the inverse

Add your answer to the number you subtracted. Does it equal the starting number?

For example: answer + 7 = 42

Support and extension

Support: Read each question aloud, use a place-value chart, build the number with tens and ones, and say “rename one ten as 10 ones”. Work with a partner if helpful.

Extension: Write a different subtraction problem that needs regrouping. Solve it using a place-value drawing and a number-line method. Check it with the inverse.

Dyslexia-friendly option: Read one question at a time, cover unused questions, use a ruler to track each line, and explain your working aloud before writing.