Addition by Partitioning worksheet for practicing addition through partitioning numbers into tens and units.

I'll solve this addition by partitioning worksheet step by step.

First, let's partition the numbers at the top:

- 28 = 20 (tens) + 8 (units)
- 12 = 10 (tens) + 2 (units)
- 63 = 60 (tens) + 3 (units)
- 90 = 90 (tens) + 0 (units)

Now for the addition problems:

1. 13 + 25
- Add the Tens: 10 + 20 = 30
- Add the Units: 3 + 5 = 8
- Final Answer: 30 + 8 = 38

2. 36 + 12
- Add the Tens: 30 + 10 = 40
- Add the Units: 6 + 2 = 8
- Final Answer: 40 + 8 = 48

3. 51 + 18
- Add the Tens: 50 + 10 = 60
- Add the Units: 1 + 8 = 9
- Final Answer: 60 + 9 = 69

4. 14 + 43
- Add the Tens: 10 + 40 = 50
- Add the Units: 4 + 3 = 7
- Final Answer: 50 + 7 = 57

5. 22 + 32
- Add the Tens: 20 + 30 = 50
- Add the Units: 2 + 2 = 4
- Final Answer: 50 + 4 = 54

6. 77 + 11
- Add the Tens: 70 + 10 = 80
- Add the Units: 7 + 1 = 8
- Final Answer: 80 + 8 = 88

7. 42 + 25
- Add the Tens: 40 + 20 = 60
- Add the Units: 2 + 5 = 7
- Final Answer: 60 + 7 = 67

8. 51 + 21
- Add the Tens: 50 + 20 = 70
- Add the Units: 1 + 1 = 2
- Final Answer: 70 + 2 = 72

9. 35 + 44
- Add the Tens: 30 + 40 = 70
- Add the Units: 5 + 4 = 9
- Final Answer: 70 + 9 = 79

Final Answer:
Top section: 28 = 2 tens + 8 units; 12 = 1 ten + 2 units; 63 = 6 tens + 3 units; 90 = 9 tens + 0 units

Addition problems:
1. 13 + 25 = 38
2. 36 + 12 = 48
3. 51 + 18 = 69
4. 14 + 43 = 57
5. 22 + 32 = 54
6. 77 + 11 = 88
7. 42 + 25 = 67
8. 51 + 21 = 72
9. 35 + 44 = 79