2
One long jump
Learner’s Book 1: Unit 13, pp. 182–183
GoalAdd by drawing one jump of the right size on a number line.
New words
long jump · one hop that covers many numbers at oncecalculation · a sum that we work outstart · the number we begin at
Explanation
Jumping one number at a time can take a long time. We can draw one long jump instead. To add 6 + 8, start at 6. Draw one jump of 8. The jump lands on 14, so 6 + 8 = 14. The jump is labelled +8. A line with one jump is quicker than a line with eight small jumps. Always ring the start number first.
Worked examples
13 + 5: start at 13 and draw one jump of 5. It lands on 18. So 13 + 5 = 18.
4 + 11: start at 4 and draw one jump of 11. It lands on 15. So 4 + 11 = 15.
Adding 0 does not move us. 9 + 0 = 9 and 0 + 6 = 6. The number stays the same.
Class activity
Jump cards: make cards with numbers 1 to 10. Draw one card for the start number and one for the jump. Draw one long jump on a number line and write the sum. Take turns with a partner.
Practice
1
What is 3 + 9? Draw one jump.
12
2
What is 12 + 6? Draw one jump.
18
3
What calculation does this number line show?
7 + 8 = 15
4
Ali starts at 15 and draws one jump of 4. Where does he land?
19