Find the Missing Number (Addition)
What number is missing? Write it in the blue box.
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This is sheet #12324601.
How to do it
- Read the problem. Find the blue box.
- Ask "What plus this makes the total?"
- Count up to find it. Write it in the box.
Teaching tip
Have your child check by reading the whole problem out loud with the answer filled in. This sheet is aligned with Common Core 1.OA.D.8.

About this worksheet
Fourteen addition problems with one number missing. Sometimes it's the first number, sometimes the second.
What kids practice
A fact family is three numbers that make two addition facts and two subtraction facts, like 6, 8 and 14. Once kids see that, they can find a missing number in a problem like 6 + ? = 14 or ? - 8 = 6. They also learn what the equal sign really means. It says both sides are the same amount, not "the answer goes next".
Watch for
- Adding every number they see, so 5 + ? = 12 gets the answer 17.
- Thinking an equation must have the answer on the right, so 9 = 4 + 5 looks "wrong".
- Putting the smaller number first in a subtraction fact.
It's free to print, with Fewer, Standard or More on the page and an answer key. See the full fact families and missing numbers guide for 1st grade.
More sheets in this set
- See it all
1. Ways to Make 10All eleven ways to make 10, with ten frames, addition facts and subtraction facts. - See it all
2. Fact Families ChartA fact family house, how to find a missing number, and what the equals sign means, with true and false examples.
3. Fact Family Houses to 20Four fact family houses with a teen number on top. Write the two addition and two subtraction facts.
5. Find the Missing Number (Mixed)Fourteen addition and subtraction problems with one number missing.
6. True or False EquationsTen equations to check, including ones with the answer on the left and math on both sides. Matches 1.OA.D.7.