This Grade 1 worksheet challenges first graders to find the missing addend in three-number equations. Four multiple choice questions ask which number completes sums like 5+4+__=12. Five fill-in problems mix the unknown position, placing it first, middle, or last inside the equation. Students practice the inverse relationship between addition and subtraction while strengthening their sense of ten-bond facts up to 20 for Grade 1 addition.
Style:
Adding Three Numbers
Part A: Multiple Choice
Circle the best answer for each question.
1. Which number completes 5 + 4 + ___ = 12?
A) 1
B) 2
C) 3
D) 4
2. 4 + ___ + 3 = 10. What is the missing number?
A) 2
B) 3
C) 4
D) 5
3. Which number completes 2 + 6 + ___ = 11?
A) 2
B) 3
C) 4
D) 5
4. 7 + 1 + ___ = 10. What number is missing?
A) 1
B) 2
C) 3
D) 4
Part B: Fill in the Blank
Write the correct answer on each line.
1. 3 + 3 + 4 = 10
2. 5 + 2 + 3 = 10
3. 3 + 4 + 2 = 9
4. 6 + 3 + 1 = 10
5. 2 + 5 + 4 = 11
Adding Three Numbers
★ Part A: Multiple Choice
Circle the best answer for each question.
1. Which number completes 5 + 4 + ___ = 12?
A) 1
B) 2
C) 3
D) 4
2. 4 + ___ + 3 = 10. What is the missing number?
A) 2
B) 3
C) 4
D) 5
3. Which number completes 2 + 6 + ___ = 11?
A) 2
B) 3
C) 4
D) 5
4. 7 + 1 + ___ = 10. What number is missing?
A) 1
B) 2
C) 3
D) 4
★ Part B: Fill in the Blank
Write the correct answer on each line.
1) 3 + 3 + 4 = 10
2) 5 + 2 + 3 = 10
3) 3 + 4 + 2 = 9
4) 6 + 3 + 1 = 10
5) 2 + 5 + 4 = 11
Ready to Practice?
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9 Questions
12-18 minutes
Auto-graded
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