How does the Kumon maths programme develop school children in Key ... - Free Printable

Let's solve each of the multiplication problems on this Kumon worksheet step by step. The task is to multiply a two-digit number by a one-digit number.

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(1)

43 × 2

Break it down:
- 3 × 2 = 6
- 40 × 2 = 80
Add them: 80 + 6 = 86

✔ Answer: 86 (already filled in)

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(2)

34 × 2

- 4 × 2 = 8
- 30 × 2 = 60
Add: 60 + 8 = 68

✔ Answer: 68

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(3)

31 × 2

- 1 × 2 = 2
- 30 × 2 = 60
Add: 60 + 2 = 62

✔ Answer: 62

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(4)

41 × 2

- 1 × 2 = 2
- 40 × 2 = 80
Add: 80 + 2 = 82

✔ Answer: 82

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(5)

13 × 2

- 3 × 2 = 6
- 10 × 2 = 20
Add: 20 + 6 = 26

✔ Answer: 26

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(6)

21 × 2

- 1 × 2 = 2
- 20 × 2 = 40
Add: 40 + 2 = 42

✔ Answer: 42

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(7)

32 × 2

- 2 × 2 = 4
- 30 × 2 = 60
Add: 60 + 4 = 64

✔ Answer: 64

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(8)

42 × 2

- 2 × 2 = 4
- 40 × 2 = 80
Add: 80 + 4 = 84

✔ Answer: 84

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✔ Final Answers:

| Problem | Answer |
|--------|--------|
| (1) | 86 |
| (2) | 68 |
| (3) | 62 |
| (4) | 82 |
| (5) | 26 |
| (6) | 42 |
| (7) | 64 |
| (8) | 84 |

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🔍 Explanation:

This worksheet teaches multiplication of a two-digit number by a single digit using the distributive property:
> $$
> (a \times b) = (tens \times b) + (units \times b)
> $$

For example:
$ 43 × 2 = (40 × 2) + (3 × 2) = 80 + 6 = 86 $

The note at the bottom shows that multiplying by 2 is the same as adding the number to itself:
> $ 43 × 2 = 43 + 43 = 86 $

This reinforces understanding of multiplication as repeated addition.

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Let me know if you'd like a printable version or a PDF of the completed sheet!