Numbers to 20 · Usually met around P1
Odd and even numbers
Look at the ones: 0, 2, 4, 6, 8 is even.
How to do it
Method
Look at the ones: 0, 2, 4, 6, 8 is even
14 → 7 pairs, none left: even
Another way
Pair them up
13 makes 6 pairs and 1 over: odd
In full
Put things in twos: if they pair up exactly, the number is even; if 1 is left over, it is odd. Just look at the ones digit: 0, 2, 4, 6 or 8 means even; 1, 3, 5, 7 or 9 means odd. From 1, odd and even take turns: 1 odd, 2 even, 3 odd, 4 even… so one even number is 2 more than the even number before it.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
17 is an even number.
True or false?
Show the answer and working
Answer: False
Look at the ones digit, 7: 0, 2, 4, 6 or 8 means even; 1, 3, 5, 7 or 9 means odd.
Example 2
Of the even numbers bigger than 16, which is the smallest?
Show the answer and working
Answer: 18
Count on from 16: the first number ending in 0, 2, 4, 6 or 8 is 18.
Example 3
From 1 to 14, there are □ odd numbers and □ even numbers.
Fill in each box
Show the answer and working
Answer: 7，7
Odd and even take turns, starting with 1 (odd): from 1 to 14, 7 are odd and 7 even.
Practise it in the game →Numbers to 20 · Free to start, unlimited questions, no download