Here's the solution to the "Horizontal Addition and Subtraction" worksheet. The goal is to find the missing number in each equation by using inverse operations (subtraction for addition problems, and addition for subtraction problems).
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Left Column Solutions:
1.
84 + ___ = 90
→ Missing number = 90 - 84 =
6
2.
25 - ___ = 20
→ Missing number = 25 - 20 =
5
3.
80 + ___ = 100
→ Missing number = 100 - 80 =
20
4.
50 + ___ = 70
→ Missing number = 70 - 50 =
20
5.
70 - ___ = 30
→ Missing number = 70 - 30 =
40
6.
64 - ___ = 60
→ Missing number = 64 - 60 =
4
7.
34 + ___ = 40
→ Missing number = 40 - 34 =
6
8.
12 - ___ = 9
→ Missing number = 12 - 9 =
3
9.
19 + ___ = 25
→ Missing number = 25 - 19 =
6
10.
29 + ___ = 40
→ Missing number = 40 - 29 =
11
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Right Column Solutions:
1.
25 + ___ = 50
→ Missing number = 50 - 25 =
25
2.
57 - ___ = 50
→ Missing number = 57 - 50 =
7
3.
35 + ___ = 70
→ Missing number = 70 - 35 =
35
4.
24 + ___ = 30
→ Missing number = 30 - 24 =
6
5.
40 - ___ = 20
→ Missing number = 40 - 20 =
20
6.
90 - ___ = 45
→ Missing number = 90 - 45 =
45
7.
30 + ___ = 40
→ Missing number = 40 - 30 =
10
8.
16 - ___ = 8
→ Missing number = 16 - 8 =
8
9.
12 + ___ = 25
→ Missing number = 25 - 12 =
13
10.
2 + ___ = 4
→ Missing number = 4 - 2 =
2
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✔ Final Answers (Fill in the boxes from top to bottom, left column then right column):
Left Column:
6, 5, 20, 20, 40, 4, 6, 3, 6, 11
Right Column:
25, 7, 35, 6, 20, 45, 10, 8, 13, 2
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📝 Explanation:
- For
addition equations like `A + ? = B`, solve by subtracting: `? = B - A`
- For
subtraction equations like `A - ? = B`, solve by subtracting: `? = A - B`
This reinforces the relationship between addition and subtraction as inverse operations — a key concept in early arithmetic.
Let me know if you’d like this formatted as a printable answer sheet!
Parent Tip: Review the logic above to help your child master the concept of math worksheet mental addition subtraction.
