Illustrative Mathematics Kindergarten, Unit 5: Composing and Decomposing Numbers to 10
In this unit, your child digs into the many ways to make each number up to 10. Kindergartners find that 7 can be 5 and 2, 4 and 3, or 6 and 1, figure out what number goes with another to make 10, and grow faster at facts within 5. These pairs deepen the last unit's adding and subtracting and lead to the teen numbers as ten and some more.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 5?
- Finding many ways to make each number up to 10, such as 7 = 5 + 2, 7 = 4 + 3, and 7 = 6 + 1. Learn more: Splitting numbers up to 10 into two parts
- Figuring out what number goes with another to make 10, often by filling the empty spaces on a ten-frame. Learn more: Finding the number that makes 10
- Getting faster at adding and subtracting within 5, such as knowing 5 - 4 = 1 without counting. Learn more about adding fluently within 5: Adding fluently within 5 · Learn more about subtracting fluently within 5
Sample questions to try together
These are real questions from our 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
There are 5 ladybugs in total. Some are on a leaf and the rest are on a flower. If 2 ladybugs are on the leaf, how many ladybugs are on the flower?
- 2
- 3
- 4
How you can help
- Hide some of 7 spoons under a towel and show the rest, then ask your child how many are hidden, trying a different number each round.
- Play 'make ten' with your fingers on a walk or ride: hold up some fingers and let your child say how many more make 10.
- Ask quick facts within 5 while setting the table, such as 'There are 3 plates out; how many more make 5?'
Where kids can get stuck
- Finding one way to make 7 and believing it is the only answer.
- Guessing for numbers other than 5, such as saying 8 needs 3 more to make 10.
- Thinking 7 = 4 + 3 is wrong because the answer is written first instead of last.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- compose
- To put smaller parts or shapes together to make something new.
- decompose
- To break a number or shape into smaller parts.
- number pair
- Two numbers that make a given number, like 4 and 2 for 6.
- make ten
- Finding the number that goes with another to make 10, like 7 and 3.
- ten-frame
- A grid of 10 boxes, in two rows of 5, used to show numbers.
- equal sign
- The = sign, which means is the same amount as.
- fact
- A small adding or subtracting problem kids learn to just know, like 2 + 2 = 4.
Want to help your child master making numbers to 10?
In Bobby's Math Club, your child practices these skills at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free.
Join the club
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.
Which math standards does Illustrative Mathematics Kindergarten Unit 5 cover?
Illustrative Mathematics Kindergarten Unit 5 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.