Finding the number that makes 10
In kindergarten, children learn to find the number that makes 10 when added to any number from 1 to 9, such as knowing that 7 needs 3 more.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our kindergarten 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
How many more dots do you need to make 10 if you already have 7 dots?
- 2
- 4
- 3
Why this matters
The pairs that make 10 are some of the most useful facts your child will ever learn, because our numbers are built in tens. In 1st grade they use them to add quickly: for 8 + 5, they know 8 needs 2 to make 10, so 8 + 5 is 10 + 3, or 13. Later the same idea helps with making 100 in 2nd grade, with counting change, and with everyday mental math.
Where kids can get stuck
- Including the starting number when counting up, so for 6 they say "6, 7, 8, 9, 10" and answer 5, not 4.
- Knowing that 5 and 5 make 10 but guessing for other numbers, such as saying 8 needs 3 more.
- Answering with 10 itself, or with the starting number, because they are unsure what "how many more" asks.
How you can help
- Put some eggs or balled-up socks in an empty egg carton cut to ten spaces, and ask your child how many more would fill it to make 10.
- Hold up some fingers, such as 6, and ask your child to show how many fingers you are hiding to make ten.
- Line up 10 toys, hide some under a towel, and ask your child how many are hiding by looking at how many are still showing.
The kid-friendly video below explains it in a few minutes, and Bobby's Math Club offers free practice that grows with your child.
Kid-friendly explanation
Questions parents ask
Why does my child need to know the numbers that make 10?
Our number system is built on tens, so knowing the pairs that make 10 is extremely useful. Children use these pairs to add larger numbers quickly in 1st grade, by making a ten first. They also help with subtraction and with understanding that a number like 14 is one ten and four ones.
My child counts on fingers to find the missing number. Is that okay?
Yes. Fingers are a natural model for ten, and using them helps your child see the pairs. Over time, with lots of practice, many pairs will become familiar enough that your child knows them without counting. Using fingers first builds understanding that memorizing alone would not.
How quickly should my child know the pairs that make 10?
By the end of kindergarten, children are expected to find the missing number for any number from 1 to 9, often using objects or drawings. Knowing them instantly is not required yet. Speed usually comes in 1st grade, as children use the pairs in addition and subtraction.
Make learning math fun
Bobby's Math Club turns kindergarten math practice into something fun to do together.
- Unlimited free practice
- A few minutes a day, at just the right level
- You see their progress and what to work on next
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 K.OA.A.4: “For any number from 1 to 9, find the number that makes 10 when added to the given number, e.g., by using objects or drawings, and record the answer with a drawing or equation.” Learn how Bobby's Math Club can help your students grow. (Common Core K.OA.4)