This worksheet guides children to count base-10 blocks, separating tens and ones before writing the total sum.

Let’s solve each part step by step. We’ll count the “tens” blocks (the tall stacks) and the “ones” blocks (the small single squares), then add them together to get the total number.

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Part a:

- Tens blocks: There are 2 tall stacks → that’s 20
- Ones blocks: There are 7 small squares → that’s 7
- Add them: 20 + 7 = 27

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Part b:

- Tens blocks: 4 tall stacks → 40
- Ones blocks: 5 small squares → 5
- Add them: 40 + 5 = 45

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Part c:

- Tens blocks: 4 tall stacks → 40
- Ones blocks: 4 small squares → 4
- Add them: 40 + 4 = 44

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Part d:

- Tens blocks: 6 tall stacks → 60
- Ones blocks: Let’s count carefully — top row has 3, middle row has 3, bottom row has 2 → 3+3+2 = 8
- Add them: 60 + 8 = 68

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Part e:

- Tens blocks: 4 tall stacks → 40
- Ones blocks: Only 1 small square → 1
- Add them: 40 + 1 = 41

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Part f:

- Tens blocks: 3 tall stacks → 30
- Ones blocks: Top row has 4, middle row has 4, bottom row has 1 → 4+4+1 = 9
- Add them: 30 + 9 = 39

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Final Answer:
a) 20 + 7 = 27
b) 40 + 5 = 45
c) 40 + 4 = 44
d) 60 + 8 = 68
e) 40 + 1 = 41
f) 30 + 9 = 39