Even and odd numbers
By the end of this lesson a child splits a number into pairs. If nothing is left over, the number is even. If one is left over, the number is odd.
What the child can do at the end
- For 6, say: three pairs, nothing left, so it is even.
- For 7, say: three pairs and one left over, so it is odd.
- Know that the even numbers up to 10 are 2, 4, 6, 8, 10.
What a pair is
A pair is two things together: two socks, two hands. An even number can be built only from such pairs. An odd number always leaves one thing without a partner.
One problem, step by step
There are 7 socks. Is 7 even or odd?
- Put the socks into pairs: first pair, second pair, third pair.
- That is 2 + 2 + 2 = 6 socks.
- The seventh sock has no partner. One is left.
- When one is left, the number is odd. 7 is odd.
A common mistake
The child sees that 7 is next to 6 and says 7 is even, because 6 is even. Being next to an even number does not decide it. The leftover does: 6 has no leftover, 7 has 1 left.
The other mistake is 10. The child says 10 is odd because it is “big”. Ten is five pairs and nothing left over, so 10 is even.
Practice
Write even or odd.
- 4
- 5
- 8
- 9
- 2
- 10
Answers
- even — two pairs
- odd — two pairs and one left over
- even
- odd
- even — one pair
- even — five pairs
Five: 2 + 2 = 4, and 1 is left. That is why 5 is odd.
After the lesson
When the child can say, without reciting a list, that 8 makes pairs and 9 does not, open addition with carrying. There, the ones cross over ten.
For a parent
Use socks or gloves, not a list of numbers. The question is always the same: did someone end up without a partner?