Adding and subtracting story problems within 20
In 1st grade, children learn to solve addition and subtraction story problems within 20, including ones where the missing number comes at the start or in the middle.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 1st grade practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
I had some toy cars. My friend gave me 3 more cars. Now I have 8 cars in total. How many toy cars did I have at first?
- 3
- 5
- 8
Why this matters
Story problems are where your child first sees that math describes real things happening in their own day. Next year the same kinds of stories grow to numbers up to 100 and to problems with two steps, and a child who pictures what is happening, rather than adding whatever numbers appear, is ready for them. Problems where the missing amount comes first, like ? + 5 = 12, are also an early taste of algebra.
Where kids can get stuck
- Adding every number out of habit, answering 20 instead of 4 for "Sam has 12 grapes and eats some. Now he has 8."
- Treating "more" as a signal to add, answering 12 instead of 6 when Lia's 9 shells are 3 more than Ben's.
- Losing track when drawing a story, mixing up which dots belong to which group and counting some of them twice.
How you can help
- Tell short stories at snack time with the start missing: "I put some crackers on your plate, then added 4, and now there are 10. How many did I put on first?"
- Act out comparing stories with two piles of toys: line up 8 cars and 5 trucks side by side and ask how many more cars there are, letting your child match them one to one.
- Ask your child to make up a story for you to solve, then check your answer together with blocks, spoons, or fingers. Inventing problems shows they understand what the numbers mean.
If it’s helpful, you can watch the kid-friendly video below, or sign up for free, adaptive practice in Bobby's Math Club.
Kid-friendly explanation
Questions parents ask
Why is my child learning word problems this way, with drawings and boxes?
Drawings and objects help your child see what is happening in the story before choosing to add or subtract. The box, as in 3 + ? = 10, gives the missing number a place to live so it can be talked about. This keeps children from guessing an operation from key words and builds the understanding that later supports solving equations.
What if my child can add and subtract but gets word problems wrong?
That is common in 1st grade. Calculating and understanding a story are different skills. Slow down and ask your child to retell the story in their own words, then act it out with objects. Once they can show what happened, the right operation usually becomes clear. Problems where the starting amount is missing are the hardest and take the longest.
Which word problems are hardest for 1st graders?
Problems where the start is unknown, like "Some birds were on a tree, 4 flew away, and 6 are left," and comparing problems that ask "how many fewer" tend to be hardest. Many children reach the end of 1st grade still building confidence with these. Plenty of acted-out stories with small numbers help more than rushing to bigger numbers.
Make learning math fun
Bobby's Math Club turns 1st grade math practice into something fun to do together.
- Unlimited practice, completely free
- Questions matched to your child’s level, a few minutes a day
- Level-ups, badges, and a cheer for every win
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
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Join the clubNote for teachers: This skill is covered by Common Core math standard 1.OA.A.1: “Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.” Learn how Bobby's Math Club can help your students grow. (Common Core 1.OA.1)