Adding and Subtracting Unknown Numbers Activity
Find the missing number in equations within 20 with this adding and subtracting unknown numbers activity for 1st and 2nd grade: matching cards, a recording sheet and practice, answer key included.
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About this resource
Description
How to Teach Finding the Unknown Number
This adding and subtracting unknown numbers activity helps children find the missing number in addition and subtraction equations within 20. The unknown number can be anywhere in the equation: at the start, in the middle, at the end, or on either side of the equal sign. Matching equation cards to answer cards turns this important 1st grade skill into a fun puzzle game for 1st and 2nd grade. An answer key is included.
How to Use the Activity
Print the equation cards and answer cards and cut on the dashed lines. Children lay the answer cards face up, pick an equation card, and find the number that makes the math true. They place the answer card beside the equation and write the number on the recording sheet. Every answer is different, so each equation has exactly one matching card. A practice worksheet gives children eight more equations to solve on their own.
What’s Included
- A colorful cover page
- A How to Use page with materials, prep and steps
- 12 lettered equation cards with the unknown in different places
- 12 answer cards
- A recording sheet
- A 1st grade practice worksheet with eight equations
- Answer keys for the recording sheet and the practice worksheet
Why This Missing Number Activity Helps Kids
First, this missing number activity shows children that the equal sign means both sides are the same, not just the answer comes next. Second, finding unknowns in every position builds a deep understanding of how addition and subtraction are related. Third, the matching game format keeps practice active and lets children check their thinking with a partner.
Ideas for Teachers and Parents
Use the adding and subtracting unknown numbers activity in a math center, a small group or as a partner game. Give children counters or a number line to check their answers. At home, write a problem like 8 plus what equals 14 and take turns making up new ones.
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