3
Stories and number sentences
Learner’s Book 1: Unit 5, pp. 71–74
GoalUse a story (first, then, now) and a part-whole diagram to write and solve an addition number sentence.
New words
part · one of the groups we put togetherwhole · all the parts togethertotal · how many altogethernumber sentence · numbers and signs, like 5 + 2 = 7
Explanation
An adding story has three steps. First, there are some. Then, some more come. Now, there are more altogether. First there are 5 chicks in a pen. Then 2 more chicks run in. Now there are 7 chicks. The number sentence is 5 + 2 = 7. A part-whole diagram shows the same idea. The two parts are the small groups. The whole is the total. When you add the two parts, you get the whole. The order does not change the total: 2 + 6 = 8 and 6 + 2 = 8.
Worked examples
First 5 chicks are in a pen. Then 2 more run in. Now there are 7 chicks: 5 + 2 = 7.
The two parts are 4 and 2. The whole (the total) is 6. 4 + 2 = 6.
6 + 2 = 8, and 2 + 6 = 8 too. Put the counters in a different order and the total stays the same.
Class activity
Story time: with toy cars, animals or buttons, act out a story. ‘First I have 4 cars. Then my friend gives me 3 more. Now I have 7.’ Make number cards for the numbers, + and =, and build the number sentence 4 + 3 = 7. Tell new stories with different numbers.
Practice
1
How many balls altogether?
6 (4 + 2 = 6)
2
What is the total?
10 (6 + 4 = 10)
3
First there are 3 cars in a car park. Then 5 more drive in. Write the number sentence.
3 + 5 = 8
4
If 7 + 3 = 10, what is 3 + 7?
10. The order does not change the total.