Addition by Partitioning worksheet for practicing addition using tens and units, designed for medium progression level.

Let's solve this "Addition by Partitioning (A)" worksheet step-by-step. The goal is to break numbers into tens and units, add the tens separately, then the units, and finally combine them for the final answer.

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🔹 Part 1: Partition the numbers into tens and units

We need to split each number into its tens and units place:

1. 28 →
- Tens: 20
- Units: 8
✔ So: Tens = 20, Units = 8

2. 12 →
- Tens: 10
- Units: 2
✔ So: Tens = 10, Units = 2

3. 63 →
- Tens: 60
- Units: 3
✔ So: Tens = 60, Units = 3

4. 90 →
- Tens: 90
- Units: 0
✔ So: Tens = 90, Units = 0

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🔹 Part 2: Addition by Partitioning

We'll now go through each addition problem using the partitioning method:
- Break each number into tens and units
- Add the tens together
- Add the units together
- Then add the two results

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#### ✔ 1. 13 + 25

- 13 = 10 + 3
- 25 = 20 + 5

| Step | Calculation |
|------|-------------|
| Add the Tens | 10 + 20 = 30 |
| Add the Units | 3 + 5 = 8 |
| Final Answer | 30 + 8 = 38 |

✔ Answer: 38

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#### ✔ 2. 36 + 12

- 36 = 30 + 6
- 12 = 10 + 2

| Step | Calculation |
|------|-------------|
| Add the Tens | 30 + 10 = 40 |
| Add the Units | 6 + 2 = 8 |
| Final Answer | 40 + 8 = 48 |

✔ Answer: 48

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#### ✔ 3. 51 + 18

- 51 = 50 + 1
- 18 = 10 + 8

| Step | Calculation |
|------|-------------|
| Add the Tens | 50 + 10 = 60 |
| Add the Units | 1 + 8 = 9 |
| Final Answer | 60 + 9 = 69 |

✔ Answer: 69

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#### ✔ 4. 14 + 43

- 14 = 10 + 4
- 43 = 40 + 3

| Step | Calculation |
|------|-------------|
| Add the Tens | 10 + 40 = 50 |
| Add the Units | 4 + 3 = 7 |
| Final Answer | 50 + 7 = 57 |

✔ Answer: 57

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#### ✔ 5. 22 + 32

- 22 = 20 + 2
- 32 = 30 + 2

| Step | Calculation |
|------|-------------|
| Add the Tens | 20 + 30 = 50 |
| Add the Units | 2 + 2 = 4 |
| Final Answer | 50 + 4 = 54 |

✔ Answer: 54

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#### ✔ 6. 77 + 11

- 77 = 70 + 7
- 11 = 10 + 1

| Step | Calculation |
|------|-------------|
| Add the Tens | 70 + 10 = 80 |
| Add the Units | 7 + 1 = 8 |
| Final Answer | 80 + 8 = 88 |

✔ Answer: 88

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#### ✔ 7. 42 + 25

- 42 = 40 + 2
- 25 = 20 + 5

| Step | Calculation |
|------|-------------|
| Add the Tens | 40 + 20 = 60 |
| Add the Units | 2 + 5 = 7 |
| Final Answer | 60 + 7 = 67 |

✔ Answer: 67

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#### ✔ 8. 51 + 21

- 51 = 50 + 1
- 21 = 20 + 1

| Step | Calculation |
|------|-------------|
| Add the Tens | 50 + 20 = 70 |
| Add the Units | 1 + 1 = 2 |
| Final Answer | 70 + 2 = 72 |

✔ Answer: 72

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#### ✔ 9. 35 + 44

- 35 = 30 + 5
- 44 = 40 + 4

| Step | Calculation |
|------|-------------|
| Add the Tens | 30 + 40 = 70 |
| Add the Units | 5 + 4 = 9 |
| Final Answer | 70 + 9 = 79 |

✔ Answer: 79

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📝 Final Answers Table:

| Question | Add the Tens | Add the Units | Final Answer |
|--------|--------------|----------------|---------------|
| 13 + 25 | 10 + 20 = 30 | 3 + 5 = 8 | 30 + 8 = 38 |
| 36 + 12 | 30 + 10 = 40 | 6 + 2 = 8 | 40 + 8 = 48 |
| 51 + 18 | 50 + 10 = 60 | 1 + 8 = 9 | 60 + 9 = 69 |
| 14 + 43 | 10 + 40 = 50 | 4 + 3 = 7 | 50 + 7 = 57 |
| 22 + 32 | 20 + 30 = 50 | 2 + 2 = 4 | 50 + 4 = 54 |
| 77 + 11 | 70 + 10 = 80 | 7 + 1 = 8 | 80 + 8 = 88 |
| 42 + 25 | 40 + 20 = 60 | 2 + 5 = 7 | 60 + 7 = 67 |
| 51 + 21 | 50 + 20 = 70 | 1 + 1 = 2 | 70 + 2 = 72 |
| 35 + 44 | 30 + 40 = 70 | 5 + 4 = 9 | 70 + 9 = 79 |

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✔ Summary of Part 1 (Partitioning):

| Number | Tens | Units |
|-------|------|-------|
| 28 | 20 | 8 |
| 12 | 10 | 2 |
| 63 | 60 | 3 |
| 90 | 90 | 0 |

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💡 Explanation of the Method:

Partitioning means breaking numbers into smaller parts (like tens and units) to make addition easier.

For example:
To add 13 + 25:
- Split: 10+3 and 20+5
- Add tens: 10+20=30
- Add units: 3+5=8
- Combine: 30+8=38

This method helps build number sense and understanding of place value.

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✔ Final Tip:

Use this strategy when adding two-digit numbers — it’s especially helpful before learning column addition or carrying over.

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