Addition and subtraction worksheet with missing numbers for elementary math practice.

Problem Description:

The task involves solving a series of addition and subtraction problems to find the missing numbers. The goal is to fill in the blanks so that each equation is correct.

Step-by-Step Solution:

#### Part 1: Basic Addition and Subtraction
1. Equation 1: \( y + 8 = 12 \)
- To solve for \( y \), subtract 8 from both sides:
\[
y = 12 - 8 = 4
\]
- So, \( y = 4 \).

2. Equation 2: \( 2 - ? = 1 \)
- Let the missing number be \( x \). Then:
\[
2 - x = 1
\]
- Solve for \( x \):
\[
x = 2 - 1 = 1
\]
- So, the missing number is \( 1 \).

3. Equation 3: \( 8 + ? = 6 \)
- Let the missing number be \( x \). Then:
\[
8 + x = 6
\]
- Solve for \( x \):
\[
x = 6 - 8 = -2
\]
- So, the missing number is \( -2 \).

4. Equation 4: \( 7 - ? = 6 \)
- Let the missing number be \( x \). Then:
\[
7 - x = 6
\]
- Solve for \( x \):
\[
x = 7 - 6 = 1
\]
- So, the missing number is \( 1 \).

---

#### Part 2: Write the Missing Numbers
1. Equation 1: \( 15 - ? = 12 \)
- Let the missing number be \( x \). Then:
\[
15 - x = 12
\]
- Solve for \( x \):
\[
x = 15 - 12 = 3
\]
- So, the missing number is \( 3 \).

2. Equation 2: \( ? + 3 = 6 \)
- Let the missing number be \( x \). Then:
\[
x + 3 = 6
\]
- Solve for \( x \):
\[
x = 6 - 3 = 3
\]
- So, the missing number is \( 3 \).

3. Equation 3: \( 8 - ? = 2 \)
- Let the missing number be \( x \). Then:
\[
8 - x = 2
\]
- Solve for \( x \):
\[
x = 8 - 2 = 6
\]
- So, the missing number is \( 6 \).

4. Equation 4: \( 9 + ? = 11 \)
- Let the missing number be \( x \). Then:
\[
9 + x = 11
\]
- Solve for \( x \):
\[
x = 11 - 9 = 2
\]
- So, the missing number is \( 2 \).

5. Equation 5: \( 8 - 0 = ? \)
- Simplify:
\[
8 - 0 = 8
\]
- So, the missing number is \( 8 \).

6. Equation 6: \( ? + 5 = 14 \)
- Let the missing number be \( x \). Then:
\[
x + 5 = 14
\]
- Solve for \( x \):
\[
x = 14 - 5 = 9
\]
- So, the missing number is \( 9 \).

7. Equation 7: \( ? + 3 = 10 \)
- Let the missing number be \( x \). Then:
\[
x + 3 = 10
\]
- Solve for \( x \):
\[
x = 10 - 3 = 7
\]
- So, the missing number is \( 7 \).

8. Equation 8: \( 6 - ? = 2 \)
- Let the missing number be \( x \). Then:
\[
6 - x = 2
\]
- Solve for \( x \):
\[
x = 6 - 2 = 4
\]
- So, the missing number is \( 4 \).

9. Equation 9: \( ? - 1 = 12 \)
- Let the missing number be \( x \). Then:
\[
x - 1 = 12
\]
- Solve for \( x \):
\[
x = 12 + 1 = 13
\]
- So, the missing number is \( 13 \).

10. Equation 10: \( 4 + ? = 7 \)
- Let the missing number be \( x \). Then:
\[
4 + x = 7
\]
- Solve for \( x \):
\[
x = 7 - 4 = 3
\]
- So, the missing number is \( 3 \).

11. Equation 11: \( 1 + ? = 4 \)
- Let the missing number be \( x \). Then:
\[
1 + x = 4
\]
- Solve for \( x \):
\[
x = 4 - 1 = 3
\]
- So, the missing number is \( 3 \).

12. Equation 12: \( ? - 4 = 1 \)
- Let the missing number be \( x \). Then:
\[
x - 4 = 1
\]
- Solve for \( x \):
\[
x = 1 + 4 = 5
\]
- So, the missing number is \( 5 \).

13. Equation 13: \( 14 - ? = 7 \)
- Let the missing number be \( x \). Then:
\[
14 - x = 7
\]
- Solve for \( x \):
\[
x = 14 - 7 = 7
\]
- So, the missing number is \( 7 \).

14. Equation 14: \( ? + 1 = 9 \)
- Let the missing number be \( x \). Then:
\[
x + 1 = 9
\]
- Solve for \( x \):
\[
x = 9 - 1 = 8
\]
- So, the missing number is \( 8 \).

15. Equation 15: \( 3 + ? = 12 \)
- Let the missing number be \( x \). Then:
\[
3 + x = 12
\]
- Solve for \( x \):
\[
x = 12 - 3 = 9
\]
- So, the missing number is \( 9 \).

16. Equation 16: \( 8 + ? = 14 \)
- Let the missing number be \( x \). Then:
\[
8 + x = 14
\]
- Solve for \( x \):
\[
x = 14 - 8 = 6
\]
- So, the missing number is \( 6 \).

17. Equation 17: \( ? + 1 = 2 \)
- Let the missing number be \( x \). Then:
\[
x + 1 = 2
\]
- Solve for \( x \):
\[
x = 2 - 1 = 1
\]
- So, the missing number is \( 1 \).

18. Equation 18: \( 12 + ? = 6 \)
- Let the missing number be \( x \). Then:
\[
12 + x = 6
\]
- Solve for \( x \):
\[
x = 6 - 12 = -6
\]
- So, the missing number is \( -6 \).

19. Equation 19: \( 18 - ? = 9 \)
- Let the missing number be \( x \). Then:
\[
18 - x = 9
\]
- Solve for \( x \):
\[
x = 18 - 9 = 9
\]
- So, the missing number is \( 9 \).

20. Equation 20: \( ? + 6 = 11 \)
- Let the missing number be \( x \). Then:
\[
x + 6 = 11
\]
- Solve for \( x \):
\[
x = 11 - 6 = 5
\]
- So, the missing number is \( 5 \).

21. Equation 21: \( 1 = 0 \)
- This equation is already balanced as it is. No missing number needed.

22. Equation 22: \( ? + 7 = 4 \)
- Let the missing number be \( x \). Then:
\[
x + 7 = 4
\]
- Solve for \( x \):
\[
x = 4 - 7 = -3
\]
- So, the missing number is \( -3 \).

23. Equation 23: \( 4 + ? = 13 \)
- Let the missing number be \( x \). Then:
\[
4 + x = 13
\]
- Solve for \( x \):
\[
x = 13 - 4 = 9
\]
- So, the missing number is \( 9 \).

24. Equation 24: \( 5 + ? = 8 \)
- Let the missing number be \( x \). Then:
\[
5 + x = 8
\]
- Solve for \( x \):
\[
x = 8 - 5 = 3
\]
- So, the missing number is \( 3 \).

25. Equation 25: \( ? + 3 = 5 \)
- Let the missing number be \( x \). Then:
\[
x + 3 = 5
\]
- Solve for \( x \):
\[
x = 5 - 3 = 2
\]
- So, the missing number is \( 2 \).

26. Equation 26: \( 18 - ? = 10 \)
- Let the missing number be \( x \). Then:
\[
18 - x = 10
\]
- Solve for \( x \):
\[
x = 18 - 10 = 8
\]
- So, the missing number is \( 8 \).

27. Equation 27: \( ? + 8 = 18 \)
- Let the missing number be \( x \). Then:
\[
x + 8 = 18
\]
- Solve for \( x \):
\[
x = 18 - 8 = 10
\]
- So, the missing number is \( 10 \).

28. Equation 28: \( 5 + ? = 12 \)
- Let the missing number be \( x \). Then:
\[
5 + x = 12
\]
- Solve for \( x \):
\[
x = 12 - 5 = 7
\]
- So, the missing number is \( 7 \).

29. Equation 29: \( ? + 4 = 0 \)
- Let the missing number be \( x \). Then:
\[
x + 4 = 0
\]
- Solve for \( x \):
\[
x = 0 - 4 = -4
\]
- So, the missing number is \( -4 \).

30. Equation 30: \( 9 - ? = 6 \)
- Let the missing number be \( x \). Then:
\[
9 - x = 6
\]
- Solve for \( x \):
\[
x = 9 - 6 = 3
\]
- So, the missing number is \( 3 \).

---

Final Answer:

\[
\boxed{
\begin{aligned}
&\text{Part 1: } y = 4, \text{ missing numbers are } 1, -2, 1 \\
&\text{Part 2: } \text{Missing numbers are } 3, 3, 6, 2, 8, 9, 7, 4, 13, 3, 3, 5, 7, 8, 9, 6, 1, -6, 9, 5, 1, -3, 9, 3, 2, 8, 10, 7, -4, 3
\end{aligned}
}
\]