Problem Description:
The task is to solve a series of addition and subtraction problems mentally. The goal is to practice mental arithmetic skills.
Solution:
We will solve each problem step by step, ensuring clarity in the calculations.
####
Column 1: Subtraction
1. \( 13 - 7 = 6 \)
2. \( 21 - 2 = 19 \)
3. \( 16 - 11 = 5 \)
4. \( 10 - 7 = 3 \)
5. \( 15 - 9 = 6 \)
6. \( 27 - 11 = 16 \)
7. \( 13 - 8 = 5 \)
8. \( 21 - 11 = 10 \)
9. \( 25 - 19 = 6 \)
10. \( 12 - 7 = 5 \)
11. \( 23 - 8 = 15 \)
12. \( 21 - 10 = 11 \)
####
Column 2: Addition
1. \( 12 + 5 = 17 \)
2. \( 12 + 13 = 25 \)
3. \( 11 + 9 = 20 \)
4. \( 3 + 18 = 21 \)
5. \( 23 + 15 = 38 \)
6. \( 7 + 15 = 22 \)
7. \( 31 + 4 = 35 \)
8. \( 15 + 7 = 22 \)
9. \( 32 + 7 = 39 \)
10. \( 13 + 9 = 22 \)
11. \( 3 + 26 = 29 \)
12. \( 5 + 19 = 24 \)
####
Column 3: Mixed Operations
1. \( 13 + 9 = 22 \)
2. \( 22 - 7 = 15 \)
3. \( 16 + 8 = 24 \)
4. \( 15 - 6 = 9 \)
5. \( 12 + 19 = 31 \)
6. \( 22 - 5 = 17 \)
7. \( 23 + 4 = 27 \)
8. \( 11 - 7 = 4 \)
9. \( 22 + 9 = 31 \)
10. \( 22 - 4 = 18 \)
11. \( 23 + 6 = 29 \)
12. \( 12 - 8 = 4 \)
Final Answers:
\[
\begin{array}{ccc}
\text{Column 1} & \text{Column 2} & \text{Column 3} \\
13 - 7 = 6 & 12 + 5 = 17 & 13 + 9 = 22 \\
21 - 2 = 19 & 12 + 13 = 25 & 22 - 7 = 15 \\
16 - 11 = 5 & 11 + 9 = 20 & 16 + 8 = 24 \\
10 - 7 = 3 & 3 + 18 = 21 & 15 - 6 = 9 \\
15 - 9 = 6 & 23 + 15 = 38 & 12 + 19 = 31 \\
27 - 11 = 16 & 7 + 15 = 22 & 22 - 5 = 17 \\
13 - 8 = 5 & 31 + 4 = 35 & 23 + 4 = 27 \\
21 - 11 = 10 & 15 + 7 = 22 & 11 - 7 = 4 \\
25 - 19 = 6 & 32 + 7 = 39 & 22 + 9 = 31 \\
12 - 7 = 5 & 13 + 9 = 22 & 22 - 4 = 18 \\
23 - 8 = 15 & 3 + 26 = 29 & 23 + 6 = 29 \\
21 - 10 = 11 & 5 + 19 = 24 & 12 - 8 = 4 \\
\end{array}
\]
Boxed Final Answer:
\[
\boxed{
\begin{array}{ccc}
6 & 17 & 22 \\
19 & 25 & 15 \\
5 & 20 & 24 \\
3 & 21 & 9 \\
6 & 38 & 31 \\
16 & 22 & 17 \\
5 & 35 & 27 \\
10 & 22 & 4 \\
6 & 39 & 31 \\
5 & 22 & 18 \\
15 & 29 & 29 \\
11 & 24 & 4 \\
\end{array}
}
\]
Parent Tip: Review the logic above to help your child master the concept of math in english worksheet.
