Furthering understanding of subtraction as decreasing an amount | Maths

Starter quiz

6 - 2 = 4 First, there were 6 apples on the plate. Then, 2 apples were taken off the plate. Now, there are 4 apples on the plate. What does the 2 represent in this story?

The amount left at the end of the story

The amount at the start of the story

The amount subtracted ✓
Which story could match this picture?

First, there were 5 birds. Then, 1 flew off. Now, there are 4 birds. ✓

First, there were 5 birds. Then, 4 flew off. Now, there are 4 birds.

First, there were 4 birds. Then, one flew in. Now, there are 5 birds.
Which equation matches this story?

8 - 5 = 3

5 + 3 = 8

8 - 3 = 5 ✓
Which equation matches the story?

7 - 3 = 4

7 - 4 = 3 ✓

3 + 4 = 7
What is the subtrahend in this problem?

3 ✓

4

5
Match the story to the equation it represents.

8 - 4 = 4

⇔

First, there were 8 cars. Then, 4 drove away. Now, there are 4 cars. ✓

5 - 5 = 0

⇔

First, there were 5 dogs. Then, 5 ran away. Now, there are 0 dogs. ✓

10 - 6 = 4

⇔

First, there were 10 birds. Then, 6 flew away. Now, there are 4 birds. ✓

A monkey has 7 bananas. She eats 5 of them. How many bananas does she have left?

4

2 ✓

7
Which equation matches this 'First, then, now' story?

6 - 5 = 1 ✓

6 - 4 = 2

6 - 1 = 5
Write an equation to represent this story.

'8 - 3 = 5' ✓
Is this number line showing an increase or a decrease from the amount at the start of the story?

Increase ✓

Decrease
Is this story showing an increase or a decrease from the first amount?

Increase ✓

Decrease
Which of these stories is correct?

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After exploring reduction, children may struggle to see partitioning as subtraction because a part is not taken away from the whole.

Make strong links between equations and different subtraction contexts by focusing on what the subtrahend represents in each case.

Subtraction - To partition one part from another (the subtrahend from the difference), or to decrease an amount by taking an amount away.
Decrease - Make something smaller in size or quantity decrease.
Addition - To find the total, or sum, by combining two or more parts (addends), or to increase an amount by adding another.
Increase - To make something larger/greater in size or quantity.