Math 1A Singapore-Making Subtraction Stories-Chapter 4.1
Making Subtraction Stories
#There are 8 birds. 3 birds fly away. 5 birds are left.
We write the number sentence:
8 – 3 = 5
This is subtraction.
It means taking away.
#There are 7 children. 2 of them are girls. There are 5 boys.
So, the number sentence is 7 – 2
= 5
#There are 9 carrots altogether. The rabbits are eating 3
carrots. 6 carrots are left.
So, the number sentence is 9 – 3
= 6
1. Make up a story for each number sentence as below.
(a) 5 – 1 = 4
(b) 9 – 3 = 6
(c) 6 – 4 = 2
(d) 6 – 6 = 0
Solution:
(a)
There are 5 frogs altogether.
1 frog jumps away.
4 frogs are left.
(b)
There are 9 fruits altogether.
3 of them are jackfruits.
There are 6 mangoes.
(c)
There are 6 children.
4 of them are boys.
There are 2 girls.
(d)
There are 6 birds.
6 birds fly away.
0 birds are left.
2. Make up as many stories as you can for each number
sentence as below.
(a) 7 – 3 =4
(b) 7 – 2 = 5
Solution:
(a)
There are 7 children in a swimming pool.
3 of them are girls.
There are 4 boys.
(b)
There are 7 children in a swimming pool.
2 children are walking away.
5 children are left.
3. Make up as many subtraction stories as you can and write a
number sentence for each story.
Solution:
(a)
There are 5 helicopters.
2 fly away.
3 helicopters are left.
Number
sentence: 5 – 2 = 3
[as per workbook exercise 20.1(a)]
(b)
There are 6 children.
2 walk away.
4 children are left.
Number
Sentence: 6 – 2 = 4
[as per workbook exercise 20.1(b)]
(c)
There are 7 boxes.
I take away 1 box.
6 boxes are left.
Number
Sentence: 7 – 1 = 6
[as per workbook exercise 20.1(c)]
(d)
There are 9 beads.
I take away 4.
5 beads are left.
Number
sentence: 9 – 4 = 5
[as per workbook exercise 20.1(d)]