1
Odd and even numbers
Learner’s Book 1: Unit 9, pp. 132–133
GoalSort numbers to 20 into odd and even by making pairs.
New words
even · a number you can share into pairs with none left overodd · a number that always has one left over when you make pairspair · two things that go together
Explanation
Some numbers are even and some are odd. Put things in pairs, two by two. If every thing has a partner, the number is even. If one thing has no partner, the number is odd. Even numbers are 2, 4, 6, 8, 10 and so on. Odd numbers are 1, 3, 5, 7, 9 and so on. On a number track they take turns: odd, even, odd, even.
Worked examples
6 stars make 3 pairs. No star is left over, so 6 is an even number.
7 balls make 3 pairs and 1 ball is left over. So 7 is an odd number.
Mia counts 14 buttons in twos: 2, 4, 6, 8, 10, 12, 14. None are left over, so 14 is even.
Class activity
Pair game: collect 20 small things such as socks, buttons or pegs. Grab a handful, count them, then put them in pairs on the table. Is anything left over? Say ‘odd’ or ‘even’. Try ten different handfuls.
Practice
1
Is the number of birds odd or even?
Even: 8 birds make 4 pairs.
2
The odd numbers are coloured. Which numbers go in the ? squares?
7 and 9
3
Which of these numbers are even: 4, 9, 14, 7?
4 and 14
4
Nodira has 11 cherries. Can she share them equally between 2 friends with none left over?
No. 11 is odd, so 1 cherry is left over.