New

New

Year 1

# Understand subtraction as decreasing an amount

I can describe and interpret subtraction stories which involve decreasing an amount and write equations to represent this.

New

New

Year 1

# Understand subtraction as decreasing an amount

I can describe and interpret subtraction stories which involve decreasing an amount and write equations to represent this.

## Lesson details

### Key learning points

- Decreasing the first amount in a story is a type of subtraction.
- It can be represented as a ‘First, then, now’ story.
- It can also be represented as an equation.
- The first amount in a ‘First, then, now’ story must be written first in an equation.

### Common misconception

Children may find the ‘then’ part of the story, where the amount changes, difficult to identify.

Draw attention to the change, talking about it as a decrease.

### Keywords

First - Before anything else.

Then - After something in time.

Now - At the present time.

Decrease - Make something smaller in size or quantity.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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## Starter quiz

Download starter quiz

### 6 Questions

Q1.

Write a subtraction equation that could represent the counters.

Q2.

What subtraction equation could represent this story?
There were 5 children altogether in the whole group.
1 had brown hair.
How many did not have brown hair?

Q3.

Alex writes this addition equation to represent the bar model.
2 + 7 = 9
Which subtraction equation could also be represented by the bar model?

Q4.

Which set of counters could represent this story?
There were 6 teddies altogether in the whole group.
4 were small teddies.
How many were not small teddies?

Q5.

Tick the subtraction equations which could be represented by this bar model.

3 + 6 = 9

Q6.

Which of these is a subtraction story?

There are 3 birds in the tree and 2 on the fence. How many birds are there?

## Exit quiz

Download exit quiz

### 6 Questions

Q1.

Alex writes an equation to match his story.
7 - 2 = 5
What does the 5 represent?

The amount at the start of the story.

The amount subtracted.

Q2.

Which story could match this picture?

First, there were 3 pencils. Then, 2 were put in. Now, there are 5 pencils.

First, there were 5 pencils. Then, 3 were taken. Now, there are 2 pencils.

Q3.

Which set of counters would represent this story?
First, there were 10 pounds in my pocket.
Then, I spent 4 pounds.
Now, there are 6 pounds in my pocket.

Q4.

Which equation matches the picture?

5 + 2 = 7

7 - 5 = 2

Q5.

Which equation matches the story?

5 - 3 = 8

8 - 5 = 3

Q6.

Write an equation to match the picture.