Problem Description:
The task involves solving a series of multiplication problems where a two-digit number is multiplied by a one-digit number. The goal is to compute the products for each problem and ensure accuracy.
Given Problems:
1. \( 43 \times 2 \)
2. \( 34 \times 2 \)
3. \( 31 \times 2 \)
4. \( 41 \times 2 \)
5. \( 13 \times 2 \)
6. \( 21 \times 2 \)
7. \( 32 \times 2 \)
8. \( 42 \times 2 \)
Solution Approach:
We will solve each multiplication problem step by step using the standard multiplication method. For each problem, we multiply the one-digit number by each digit of the two-digit number, taking care of any carry-over values.
---
####
Problem (1): \( 43 \times 2 \)
\[
\begin{array}{r}
43 \\
\times 2 \\
\hline
86 \\
\end{array}
\]
- Multiply \( 3 \times 2 = 6 \).
- Multiply \( 4 \times 2 = 8 \).
- Combine the results: \( 86 \).
Answer: \( 86 \)
---
####
Problem (2): \( 34 \times 2 \)
\[
\begin{array}{r}
34 \\
\times 2 \\
\hline
68 \\
\end{array}
\]
- Multiply \( 4 \times 2 = 8 \).
- Multiply \( 3 \times 2 = 6 \).
- Combine the results: \( 68 \).
Answer: \( 68 \)
---
####
Problem (3): \( 31 \times 2 \)
\[
\begin{array}{r}
31 \\
\times 2 \\
\hline
62 \\
\end{array}
\]
- Multiply \( 1 \times 2 = 2 \).
- Multiply \( 3 \times 2 = 6 \).
- Combine the results: \( 62 \).
Answer: \( 62 \)
---
####
Problem (4): \( 41 \times 2 \)
\[
\begin{array}{r}
41 \\
\times 2 \\
\hline
82 \\
\end{array}
\]
- Multiply \( 1 \times 2 = 2 \).
- Multiply \( 4 \times 2 = 8 \).
- Combine the results: \( 82 \).
Answer: \( 82 \)
---
####
Problem (5): \( 13 \times 2 \)
\[
\begin{array}{r}
13 \\
\times 2 \\
\hline
26 \\
\end{array}
\]
- Multiply \( 3 \times 2 = 6 \).
- Multiply \( 1 \times 2 = 2 \).
- Combine the results: \( 26 \).
Answer: \( 26 \)
---
####
Problem (6): \( 21 \times 2 \)
\[
\begin{array}{r}
21 \\
\times 2 \\
\hline
42 \\
\end{array}
\]
- Multiply \( 1 \times 2 = 2 \).
- Multiply \( 2 \times 2 = 4 \).
- Combine the results: \( 42 \).
Answer: \( 42 \)
---
####
Problem (7): \( 32 \times 2 \)
\[
\begin{array}{r}
32 \\
\times 2 \\
\hline
64 \\
\end{array}
\]
- Multiply \( 2 \times 2 = 4 \).
- Multiply \( 3 \times 2 = 6 \).
- Combine the results: \( 64 \).
Answer: \( 64 \)
---
####
Problem (8): \( 42 \times 2 \)
\[
\begin{array}{r}
42 \\
\times 2 \\
\hline
84 \\
\end{array}
\]
- Multiply \( 2 \times 2 = 4 \).
- Multiply \( 4 \times 2 = 8 \).
- Combine the results: \( 84 \).
Answer: \( 84 \)
---
Final Answers:
\[
\boxed{
\begin{aligned}
& (1) \, 86, \, (2) \, 68, \, (3) \, 62, \, (4) \, 82, \\
& (5) \, 26, \, (6) \, 42, \, (7) \, 64, \, (8) \, 84.
\end{aligned}
}
\]
Parent Tip: Review the logic above to help your child master the concept of kumon level i math test.
