Practice 2-12: A math worksheet for students to practice evaluating equations and writing equations from word problems.

Let’s go step by step through each problem. We’ll check if the equation is true for the given value of the variable — that means we plug in the number and see if both sides are equal.

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1. x + 5 = 17, x = 22
Plug in: 22 + 5 = 27 → 27 ≠ 17 → False

2. 3 - y = 1, y = 2
Plug in: 3 - 2 = 1 → 1 = 1 → True

3. 4x = 24, x = 6
Plug in: 4 × 6 = 24 → 24 = 24 → True

4. g - 7 = 11, g = 18
Plug in: 18 - 7 = 11 → 11 = 11 → True

5. s ÷ 7 = 3, s = 21
Plug in: 21 ÷ 7 = 3 → 3 = 3 → True

6. u + 12 = 31, u = 20
Plug in: 20 + 12 = 32 → 32 ≠ 31 → False

7. h - 13 = 21, h = 34
Plug in: 34 - 13 = 21 → 21 = 21 → True

8. 64 ÷ n = 16, n = 8
Plug in: 64 ÷ 8 = 8 → 8 ≠ 16 → False

9. 20 × t = 300, t = 160
Plug in: 20 × 160 = 3200 → 3200 ≠ 300 → False

10. 18 - c = 10, c = 8
Plug in: 18 - 8 = 10 → 10 = 10 → True

11. m + 40 = 92, m = 50
Plug in: 50 + 40 = 90 → 90 ≠ 92 → False

12. x ÷ 5 = 15, x = 75
Plug in: 75 ÷ 5 = 15 → 15 = 15 → True

13. 3k = 27, k = 9
Plug in: 3 × 9 = 27 → 27 = 27 → True

14. z - 9 = 61, z = 52
Plug in: 52 - 9 = 43 → 43 ≠ 61 → False

15. 12 + v = 21, v = 7
Wait — 12 + 7 = 19 → 19 ≠ 21 → False
*(Note: If v were 9, it would be true — but here v=7)*

16. 5w = 20, w = 4
Plug in: 5 × 4 = 20 → 20 = 20 → True

17. n - 6 = 24, n = 18
Plug in: 18 - 6 = 12 → 12 ≠ 24 → False

18. k ÷ 8 = 9, k = 56
Plug in: 56 ÷ 8 = 7 → 7 ≠ 9 → False

19. m + 12 = 61, m = 49
Plug in: 49 + 12 = 61 → 61 = 61 → True

20. j + 17 = 86, j = 79
Plug in: 79 + 17 = 96 → 96 ≠ 86 → False

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Now, write an equation for each situation:

21. Jim had 18 CDs. He bought x more. Then he had 21 CDs.
Start with 18, add x, end with 21 → 18 + x = 21

22. Rolando baked 4 loaves of bread, each weighing w oz. The total weight was 80 oz.
4 times w equals 80 → 4w = 80

23. Veronica had m marbles. She gave 5 to Marco. She had 12 marbles left.
Start with m, subtract 5, end with 12 → m - 5 = 12

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Final Answer:

1. False
2. True
3. True
4. True
5. True
6. False
7. True
8. False
9. False
10. True
11. False
12. True
13. True
14. False
15. False
16. True
17. False
18. False
19. True
20. False
21. 18 + x = 21
22. 4w = 80
23. m - 5 = 12