A number is even if it can be shared into two equal whole groups, and odd if one is left over. You only need the ones digit to tell: 0, 2, 4, 6 and 8 are even, and 1, 3, 5, 7 and 9 are odd. So 34 is even because it ends in 4, and 25 is odd because it ends in 5. Zero counts as even, so numbers ending in 0 — like 40 — are even. Do not add the digits or look at the first digit.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- even
- splits into two equal groups (ends in 0, 2, 4, 6, 8)
- odd
- has one left over (ends in 1, 3, 5, 7, 9)
Worked examples
Is 34 odd or even?
- 1.Ones digit is 4.
- 2.4 is even, so 34 is even.
= even
Is 25 odd or even?
- 1.Ones digit is 5.
- 2.5 is odd, so 25 is odd.
= odd
Is 40 odd or even?
- 1.Ones digit is 0.
- 2.0 is even, so 40 is even.
= even
For parents
Method: Pair up counters — no leftover means even, one leftover means odd.
What to say: Ask only 'what is the last digit?' and check if it is in the even list.
Common mistakes:
- Adding the digits and judging from the total (34 read as odd).
- Looking at the first digit (25 read as even).
- Thinking a number ending in 0 is odd.