Number Bonds Worksheet for practicing addition with missing numbers.

Problem Description:

The image shows a "Number Bonds Worksheet" where students are required to fill in the missing numbers in each equation. Each equation is structured as follows:

\[
\text{Number 1} + \text{Missing Number} = \text{Total}
\]

The goal is to determine the missing number that, when added to the given number, results in the total provided.

---

Solution Approach:

For each problem, we will use the formula:

\[
\text{Missing Number} = \text{Total} - \text{Number 1}
\]

We will solve each part step by step.

---

Detailed Solutions:

#### Row 1:
1. 1a. \( 9 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 9 = 4
\]
Answer: 4

2. 1b. \( 3 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 3 = 10
\]
Answer: 10

3. 1c. \( \_\_ + 2 = 13 \)
\[
\text{Missing Number} = 13 - 2 = 11
\]
Answer: 11

#### Row 2:
4. 2a. \( \_\_ + 4 = 13 \)
\[
\text{Missing Number} = 13 - 4 = 9
\]
Answer: 9

5. 2b. \( 0 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 0 = 13
\]
Answer: 13

6. 2c. \( \_\_ + 1 = 13 \)
\[
\text{Missing Number} = 13 - 1 = 12
\]
Answer: 12

#### Row 3:
7. 3a. \( 1 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 1 = 12
\]
Answer: 12

8. 3b. \( \_\_ + 3 = 13 \)
\[
\text{Missing Number} = 13 - 3 = 10
\]
Answer: 10

9. 3c. \( 7 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 7 = 6
\]
Answer: 6

#### Row 4:
10. 4a. \( 6 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 6 = 7
\]
Answer: 7

11. 4b. \( \_\_ + 5 = 13 \)
\[
\text{Missing Number} = 13 - 5 = 8
\]
Answer: 8

12. 4c. \( 5 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 5 = 8
\]
Answer: 8

#### Row 5:
13. 5a. \( \_\_ + 12 = 13 \)
\[
\text{Missing Number} = 13 - 12 = 1
\]
Answer: 1

14. 5b. \( 10 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 10 = 3
\]
Answer: 3

15. 5c. \( 12 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 12 = 1
\]
Answer: 1

#### Row 6:
16. 6a. \( 2 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 2 = 11
\]
Answer: 11

17. 6b. \( 11 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 11 = 2
\]
Answer: 2

18. 6c. \( 13 + \_\_ = 13 \)
\[
\text{Missing Number} = 13 - 13 = 0
\]
Answer: 0

---

Final Answers:

\[
\boxed{
\begin{array}{ccc}
1a. & 4 & 1b. & 10 & 1c. & 11 \\
2a. & 9 & 2b. & 13 & 2c. & 12 \\
3a. & 12 & 3b. & 10 & 3c. & 6 \\
4a. & 7 & 4b. & 8 & 4c. & 8 \\
5a. & 1 & 5b. & 3 & 5c. & 1 \\
6a. & 11 & 6b. & 2 & 6c. & 0 \\
\end{array}
}
\]