Illustrative Mathematics Kindergarten, Unit 6: Numbers 10-20 and Counting to 100
In this unit, your child's number world expands. Kindergartners see each teen number as ten and some extra ones, count past 20 and on toward 100 by ones and tens, and begin counting from a number other than 1. The ways to make 10 from the previous unit help the teen numbers make sense, and next your child compares objects by length and weight.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 6?
- Counting past 20 and on to 100 by ones, and counting by tens to 100, noticing the pattern of the tens. Learn more about counting to 100 by ones: Counting to 100 by ones · Learn more about counting to 100 by tens
- Counting on from a number other than 1, such as 18 or 45, without starting over. Learn more: Counting on from any number
- Seeing each teen number as 10 and some extra ones, such as 12 = 10 + 2, using objects, drawings, and equations. Learn more: Teen numbers as ten and some more
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
What comes next? 10, 20, 30, 40, __
- 60
- 50
- 41
How you can help
- Count to 100 by tens with a clap on each ten, then count by ones from a number like 45 up to the next ten.
- Line up 10 spoons in a row and a few more below, and ask your child to name the teen number as ten and some more.
- Start counting at a number other than 1 while waiting in line, such as 18, and let your child count on until you move up.
Where kids can get stuck
- Starting again from 1 to find what comes next, even after counting '17, 18, 19' correctly.
- Saying 'ten-ty' after 90, not yet knowing that 100 comes next.
- Showing 12 with 1 object and 2 objects, thinking the 1 means just one thing.
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
- teen numbers
- The numbers 11 to 19, each made of ten and some more ones.
- ten ones
- Ten single things, which together make one ten.
- count on
- To start counting from a number other than 1, like 23, 24, 25.
- count by tens
- Saying 10, 20, 30, and so on, up to 100.
- hundred
- The number 100, which is the same as ten tens.
- equation
- A math sentence with an equal sign, like 3 + 2 = 5.
Ready to build your child’s confidence with teen numbers and counting on?
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 6 cover?
Illustrative Mathematics Kindergarten Unit 6 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.