4
Doubles
Learner’s Book 1: Unit 13, p. 197
GoalKnow and work out doubles from double 0 to double 10.
New words
double · a number added to itselfeven number · a number we can share into two equal groups with none leftequal · the same
Explanation
A double is a number added to itself. Double 4 means 4 + 4 = 8. We can see a double in two equal groups, or in a domino with the same number of spots on both halves. Knowing doubles helps us add quickly. Double 1 is 2, double 2 is 4, double 3 is 6, double 4 is 8 and double 5 is 10. Every double is an even number, because it splits into two equal groups.
Worked examples
Double 2 is 4 and double 3 is 6. Each domino has the same number on both halves.
Two equal groups of 5 stars: 5 + 5 = 10. Double 5 is 10.
| number | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|
| double | 12 | 14 | 16 | 18 | 20 |
Class activity
Doubles dice: roll a dice and say its double. Check by putting out two equal rows of beans and counting them all. Then try bigger doubles with two ten frames. Which doubles do you already know without counting?
Practice
1
What is double 3? Count the two groups.
6
2
The frames show 8 blue and 8 orange counters. What is double 8?
16
3
What is double 9?
18
4
Ana has 6 beads in each hand. How many beads does she have altogether?
12 (double 6)