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Missing Addends - Worksheet 10 - 1st Grade

Hard

Find the missing number in addition equations (Hard)

23 problems · 10-15 minutes · Skills: addition, algebraic thinking

About This Worksheet

This hard-level worksheet contains 23 problems designed for 1st Grade students practicing missing addends. Hard worksheets feature challenging problems including multi-step questions, missing values, and real-world applications to push students further.

Missing addend problems introduce algebraic thinking — finding an unknown value. This prepares students for equation solving in later grades.

How to Solve: Worked Example

Example Problem: ___ + 8 = 17
Solution Steps:
  1. The missing number is on the left side.
  2. Use subtraction: 17 − 8 = 9.
  3. Check: 9 + 8 = 17. Correct!
Answer: 9
Tip: It doesn't matter which side the blank is on — always subtract the known part from the total.
1
5 + ___ = 13
2
___ + 8 = 12
3
___ + 7 = 13
4
___ + 3 = 14
5
___ + 4 = 14
6
___ + 4 = 12
7
___ + 10 = 18
8
3 + ___ = 15
9
___ + 6 = 17
10
___ + 6 = 14
11
7 + ___ = 16
12
4 + ___ = 15
13
___ + 11 = 15
14
14 + ___ = 19
15
8 + ___ = 17
16
8 + ___ = 18
17
___ + 11 = 15
18
11 + ___ = 19
19
10 + ___ = 16
20
5 + ___ = 19
21
10 + ___ = 14
22
13 + ___ = 16
23
6 + ___ = 20

Answer Key

1. 82. 43. 64. 115. 106. 87. 88. 129. 1110. 811. 912. 1113. 414. 515. 916. 1017. 418. 819. 620. 1421. 422. 323. 14

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How many problems are on this worksheet?

This worksheet contains 23 problems. It typically takes 10-15 minutes to complete. An answer key with all solutions is included.