Missing Addend Worksheets Within 20
Teach the blank as an unknown part of a total.
Teaching notes for parents and teachers
How to teach it
Model 8 + □ = 13 with counters. Keep eight visible and ask the student to find how many more are needed.
Example to work through together
Use the model below as you explain the example. Have your student point to the quantities as you discuss them.
Whole bracelet: 12 beads.
Beads already on the string: 8.
8 + ? = 12
12 − 8 = 4
8 + 4 = 12
Ask your student
What number would make both sides equal?
If your student needs help
If the student adds the two printed numbers, point to the total and ask which part is still missing.
Make a practice set
Select the worksheet, answer key, or both. When both are selected, the answer key prints after the questions. Keep it separate if you want your student to work independently.
After your student finishes
Choose one equation and ask the child to replace the blank with their number, then read both sides aloud. If it is incorrect, decide whether they found the total instead of the missing part or counted the starting number. Use counters for that example before trying another fresh set.
Word problemsBar Model Word Problems
Use a whole-and-parts diagram to find the total, the starting amount, or the amount used.
4 problems · Answer key included
Word problemsHow Many More? Word Problems Within 20
Find the amount to add to reach a target. Fill the empty spaces and check the missing part.
4 problems · Answer key included
More about addition · Grade 1 worksheets
Grade 1 selected skill connection: 1.OA.D.8 (missing second addend only). See the Common Core standards for this grade. This worksheet does not cover every requirement in the standard.