Odd and even numbers
In 2nd grade, children learn to tell whether a group of up to 20 objects is odd or even and to write an even number as a double, like 8 = 4 + 4.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 2nd 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
Is 16 an even or odd number?
- Even
- Odd
- Neither
Why this matters
Odd and even numbers are often the first pattern your child spots inside the numbers themselves. The idea comes up throughout later math, from noticing in 3rd grade that any number times 2 is even to checking whether a group can be split fairly between two people. Writing 14 = 7 + 7 also strengthens doubles facts, and knowing that odd plus odd is always even helps your child check answers.
Where kids can get stuck
- Judging odd or even by size, thinking a large number like 18 must be odd or every small number is even.
- Pairing objects but skipping one or counting a pair twice, so a group of 10 looks odd.
- Writing an even number as any two addends, such as 12 = 5 + 7, rather than as a double like 6 + 6.
How you can help
- Match socks from the laundry and ask whether everything had a partner. Count the socks, decide if the number is odd or even, and write the double together, such as 10 = 5 + 5.
- Share a snack between two people and ask whether it can be split evenly with none left over. If one cracker is left, talk about why that means the number is odd.
- Count by twos while walking, climbing stairs, or setting the table with pairs of forks and spoons, and ask your child to notice which numbers they say and which they skip.
The kid-friendly video below is a nice one to watch together. For more, Bobby's Math Club has free practice at your child’s level.
Kid-friendly explanation
Questions parents ask
Why is my child learning odd and even by pairing objects?
Pairing objects shows what odd and even really mean: even groups can be split into pairs or two equal groups, and odd groups always have one left over. Once this makes sense, the pattern of last digits becomes something your child understands rather than a rule to memorize.
Is zero odd or even?
Zero is even. It can be split into two equal groups of 0, and it fits the pattern of even numbers: 0, 2, 4, 6. Children often wonder about this, and it is a good question to talk through by asking what happens when you count by twos starting from zero.
What does an equation with two equal addends mean?
An addend is a number being added. Two equal addends means adding a number to itself, like 7 + 7 = 14. In 2nd grade, children show that a number is even by writing it this way. If a number cannot be written as a double of a whole number, it is odd.
Make learning math fun
Bobby's Math Club turns 2nd grade math practice into something fun to do together.
- Unlimited practice, completely free
- A few minutes a day, at just the right level
- Hints when they are stuck, and a celebration when it clicks
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 2.OA.C.3: “Determine whether a group of objects (up to 20) has an odd or even number of members, e.g., by pairing objects or counting them by 2s; write an equation to express an even number as a sum of two equal addends.” Learn how Bobby's Math Club can help your students grow. (Common Core 2.OA.3)