Even and Odd Numbers

Grade 1 · Math · Study Guide

Learn what makes a number even or odd and how to tell them apart.

Every whole number is either even or odd. Even numbers can be split into two equal groups with nothing left over. The ones digit of an even number is always 0, 2, 4, 6, or 8. For example, 4 is even because 4 ÷ 2 = 2 with nothing left. You can make 2 equal groups of 2.

Odd numbers cannot be split into two equal groups — there is always one left over. The ones digit of an odd number is always 1, 3, 5, 7, or 9. For example, 7 is odd because if you try to split 7 into two groups, one group has 4 and the other has 3 — not equal.

A great way to check is the partner test: if every item has a partner, the number is even. If one item is left without a partner, the number is odd. You can also remember the pattern: even and odd numbers alternate — 1 (odd), 2 (even), 3 (odd), 4 (even), and so on.

Even vs. Odd — The Pattern
Number	Even or Odd?	Ones Digit
1	Odd	1
2	Even	2
3	Odd	3
4	Even	4
5	Odd	5
6	Even	6
7	Odd	7
8	Even	8
9	Odd	9
10	Even	0

Key terms

even number: A number that can be split into two equal groups with nothing left over (ends in 0, 2, 4, 6, or 8)
odd number: A number that cannot be split into two equal groups — one is always left over (ends in 1, 3, 5, 7, or 9)
ones digit: The digit in the rightmost place of a number that tells us if it is even or odd

Flashcards

Even Number: A number that can be split into 2 equal groups; ends in 0, 2, 4, 6, or 8
Odd Number: A number that cannot be split equally; one is always left over; ends in 1, 3, 5, 7, or 9
Is 8 even or odd?: Even — 8 ends in 8 and can be split into two groups of 4
Is 13 even or odd?: Odd — 13 ends in 3, so one is always left over
Partner Test: If everything has a partner (pair), the number is even. If one is left out, it is odd.
Is 20 even or odd?: Even — 20 ends in 0

Practice questions

Which number is even?
1. 7
2. 9
3. 11
4. 14
Show answer
Answer: 14
14 ends in 4, which is an even digit; 7, 9, and 11 all end in odd digits
The number 15 is even.
Show answer
Answer: False
15 ends in 5, which is an odd digit; 15 is odd
An even number always ends in 0, 2, 4, 6, or ___.
Show answer
Answer: 8
Even numbers end in 0, 2, 4, 6, or 8
Tanya has 12 apples. Can she share them equally between 2 friends with nothing left over?
1. No, 12 is odd
2. Yes, 12 is even
3. No, 12 cannot be shared
4. Yes, but one apple is left
Show answer
Answer: Yes, 12 is even
12 is even (ends in 2); it splits into two equal groups of 6
Which ones digit tells you a number is ODD?
1. 0
2. 4
3. 7
4. 8
Show answer
Answer: 7
7 is an odd digit (1, 3, 5, 7, 9 are odd ones digits)

Fun facts

Zero (0) is an even number — it can be split into two equal groups of zero!
When you add two even numbers together, the answer is always even. When you add two odd numbers, the answer is always even too!

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