1
Pairs: even or odd?
Learner’s Book 1: Unit 1, pp. 31–32
GoalPut objects into pairs and say if a number is even (none left over) or odd (one left over).
New words
pair · two things that go together, like 2 shoeseven · can be put into pairs with none left overodd · always has 1 left over when put into pairs
Explanation
A pair is 2 things that go together, like 2 shoes. Some numbers are even. An even number of objects can be put into pairs with none left over. Some numbers are odd. An odd number of objects always has 1 left over. To find out, put the objects into pairs. 4 is even: there are 2 pairs. 5 is odd: there are 2 pairs and 1 left over.
Worked examples
Put 4 stars into pairs. There are 2 pairs and none left over. So 4 is an even number.
Put 3 apples into pairs. There is 1 pair and 1 apple is left over. So 3 is an odd number.
Is 6 odd or even? Make pairs of cherries: 3 pairs and none left over. So 6 is even.
Class activity
Pair up: take up to 10 buttons, socks or spoons. Make pairs. Is there one left over? Say odd or even. Try it with 1, 2, 3 and all the way to 10 things.
Practice
1
Is 8 odd or even? Put the cars into pairs to find out.
Even. There are 4 pairs and none left over.
2
Is 7 odd or even? Put the flowers into pairs.
Odd. There are 3 pairs and 1 left over.
3
Is 1 odd or even?
Odd. There is no pair, and 1 is left over.
4
Is 10 odd or even?
Even. There are 5 pairs.