Addition and Subtraction of Abacus worksheet - Free Printable

Problem Description:

The task involves performing arithmetic operations (addition and subtraction) on given numbers. Each cell in the table contains a starting number and two operations: one addition and one subtraction. The goal is to compute the results of these operations for each cell.

Solution Approach:

1. Identify the structure: Each cell has:
- A starting number.
- Two operations: one addition and one subtraction.
2. Perform the operations:
- Add the given positive value to the starting number.
- Subtract the given negative value from the starting number.
3. Record the results in the corresponding cells below the operations.

Step-by-Step Solution:

#### First Row (No.1 to No.10):
1. No.1:
- Starting number: 2
- Addition: \( 2 + 2 = 4 \)
- Subtraction: \( 2 - 2 = 0 \)
- Results: \( 4, 0 \)

2. No.2:
- Starting number: 4
- Addition: \( 4 - 1 = 3 \)
- Subtraction: \( 4 - 2 = 2 \)
- Results: \( 3, 2 \)

3. No.3:
- Starting number: 4
- Addition: \( 4 - 3 = 1 \)
- Subtraction: \( 4 + 2 = 6 \)
- Results: \( 1, 6 \)

4. No.4:
- Starting number: 2
- Addition: \( 2 + 1 = 3 \)
- Subtraction: \( 2 + 1 = 3 \)
- Results: \( 3, 3 \)

5. No.5:
- Starting number: 3
- Addition: \( 3 - 2 = 1 \)
- Subtraction: \( 3 + 1 = 4 \)
- Results: \( 1, 4 \)

6. No.6:
- Starting number: 1
- Addition: \( 1 + 3 = 4 \)
- Subtraction: \( 1 - 2 = -1 \)
- Results: \( 4, -1 \)

7. No.7:
- Starting number: 2
- Addition: \( 2 + 1 = 3 \)
- Subtraction: \( 2 - 3 = -1 \)
- Results: \( 3, -1 \)

8. No.8:
- Starting number: 3
- Addition: \( 3 - 3 = 0 \)
- Subtraction: \( 3 + 4 = 7 \)
- Results: \( 0, 7 \)

9. No.9:
- Starting number: 4
- Addition: \( 4 - 2 = 2 \)
- Subtraction: \( 4 + 1 = 5 \)
- Results: \( 2, 5 \)

10. No.10:
- Starting number: 3
- Addition: \( 3 - 2 = 1 \)
- Subtraction: \( 3 + 3 = 6 \)
- Results: \( 1, 6 \)

#### Second Row (No.11 to No.20):
11. No.11:
- Starting number: 21
- Addition: \( 21 + 12 = 33 \)
- Subtraction: \( 21 - 10 = 11 \)
- Results: \( 33, 11 \)

12. No.12:
- Starting number: 87
- Addition: \( 87 + 11 = 98 \)
- Subtraction: \( 87 - 43 = 44 \)
- Results: \( 98, 44 \)

13. No.13:
- Starting number: 77
- Addition: \( 77 - 22 = 55 \)
- Subtraction: \( 77 + 11 = 88 \)
- Results: \( 55, 88 \)

14. No.14:
- Starting number: 88
- Addition: \( 88 + 11 = 99 \)
- Subtraction: \( 88 - 99 = -11 \)
- Results: \( 99, -11 \)

15. No.15:
- Starting number: 10
- Addition: \( 10 + 55 = 65 \)
- Subtraction: \( 10 - 40 = -30 \)
- Results: \( 65, -30 \)

16. No.16:
- Starting number: 35
- Addition: \( 35 + 5 = 40 \)
- Subtraction: \( 35 + 5 = 40 \)
- Results: \( 40, 40 \)

17. No.17:
- Starting number: 10
- Addition: \( 10 + 40 = 50 \)
- Subtraction: \( 10 - 50 = -40 \)
- Results: \( 50, -40 \)

18. No.18:
- Starting number: 25
- Addition: \( 25 + 15 = 40 \)
- Subtraction: \( 25 - 10 = 15 \)
- Results: \( 40, 15 \)

19. No.19:
- Starting number: 99
- Addition: \( 99 - 77 = 22 \)
- Subtraction: \( 99 - 2 = 97 \)
- Results: \( 22, 97 \)

20. No.20:
- Starting number: 42
- Addition: \( 42 - 8 = 34 \)
- Subtraction: \( 42 + 2 = 44 \)
- Results: \( 34, 44 \)

Final Answer:

The completed table with results is as follows:

| No.1 | No.2 | No.3 | No.4 | No.5 | No.6 | No.7 | No.8 | No.9 | No.10 |
|------|------|------|------|------|------|------|------|------|-------|
| 2 | 4 | 4 | 2 | 3 | 1 | 2 | 3 | 4 | 3 |
| +2 | -1 | -3 | +1 | -2 | +3 | +1 | -3 | -2 | -2 |
| -2 | -2 | +2 | +1 | +1 | -2 | -3 | +4 | +1 | +3 |
| 4 | 3 | 1 | 3 | 1 | 4 | 3 | 0 | 2 | 1 |
| 0 | 2 | 6 | 3 | 4 | -1 | -1 | 7 | 5 | 6 |

| No.11 | No.12 | No.13 | No.14 | No.15 | No.16 | No.17 | No.18 | No.19 | No.20 |
|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|
| 21 | 87 | 77 | 88 | 10 | 35 | 10 | 25 | 99 | 42 |
| +12 | +11 | -22 | +11 | +55 | +5 | +40 | +15 | -77 | -8 |
| -10 | -43 | +11 | -99 | -40 | +5 | -50 | -10 | -2 | +2 |
| 33 | 98 | 55 | 99 | 65 | 40 | 50 | 40 | 22 | 34 |
| 11 | 44 | 88 | -11 | -30 | 40 | -40 | 15 | 97 | 44 |

Thus, the final answer is:

\[
\boxed{
\begin{array}{c|c|c|c|c|c|c|c|c|c}
\text{No.1} & \text{No.2} & \text{No.3} & \text{No.4} & \text{No.5} & \text{No.6} & \text{No.7} & \text{No.8} & \text{No.9} & \text{No.10} \\
\hline
4 & 3 & 1 & 3 & 1 & 4 & 3 & 0 & 2 & 1 \\
0 & 2 & 6 & 3 & 4 & -1 & -1 & 7 & 5 & 6 \\
\end{array}
\quad
\begin{array}{c|c|c|c|c|c|c|c|c|c}
\text{No.11} & \text{No.12} & \text{No.13} & \text{No.14} & \text{No.15} & \text{No.16} & \text{No.17} & \text{No.18} & \text{No.19} & \text{No.20} \\
\hline
33 & 98 & 55 & 99 & 65 & 40 & 50 & 40 & 22 & 34 \\
11 & 44 & 88 & -11 & -30 & 40 & -40 & 15 & 97 & 44 \\
\end{array}
}
\]