Illustrative Mathematics Grade 2, Unit 8: Equal Groups
In this unit, your child works with equal groups. They find out whether a number is odd or even by making pairs or two equal rows, write even numbers as doubles, and add the rows of an array to find a total. These ideas prepare your child for multiplication in 3rd grade, and a review of the whole year comes next.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 8?
- Deciding if a number of objects is odd or even by pairing them or splitting them into two equal teams. Learn more: Odd and even numbers
- Finding the total in rectangular arrays by adding rows or columns, and writing equations like 2 + 2 + 2 + 2 + 2 = 10. Learn more: Counting objects in equal rows by adding
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
Is 16 an even or odd number?
- Even
- Odd
- Neither
How you can help
- Split a pile of blocks or crayons into two equal teams, and ask whether there's one left over. Talk about odd and even.
- Arrange chairs, cups, or toys into rows and columns, and ask your child to write the repeated addition for it.
- Point out arrays on a walk, like the windows on a building, and ask how many there are by adding the rows.
Where kids can get stuck
- Deciding a number is odd because its first digit is odd, like calling 34 odd.
- Writing 4 + 4 for 3 rows of 4, after losing track of the rows.
- Adding the rows and columns together, answering 9 for 4 rows of 5.
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
- odd
- A number that can't be split into pairs without one left over, like 7.
- even
- A number that can be split into pairs with none left over, like 8.
- pair
- A group of two.
- array
- Objects arranged in equal rows and columns.
- row
- A line of objects going across.
- column
- A line of objects going up and down.
- equal groups
- Groups that all have the same number of objects.
- repeated addition
- Adding the same number again and again, like 4 + 4 + 4.
Ready to build your child’s confidence with equal groups?
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.
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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 Grade 2 Unit 8 cover?
Illustrative Mathematics Grade 2 Unit 8 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.