Make something smaller in size or quantity.

Understand subtraction as decreasing an amount

Maths

In this unit pupils will find missing addends in equations. They will partition a whole into 2 parts representing first, then, now stories with subtraction equations. They will learn + and - are inverse operations. In the future unit pupils will explain that addition is commutative. They will find pairs of numbers to 10 and add or subtract 1 from any number.

In prior learning, pupils will have learnt to count confidently and have developed a deep understanding of the numbers to 10, the relationships between them and the patterns within those numbers. In this unit pupils will find missing addends. They will partition a whole into two parts and represent it with subtraction equations learning that addition and subtraction are inverse operations.

Additive structures: addition and subtraction

The amount left at the end of the story. 

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

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

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.

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. 

Write a subtraction equation that could represent the counters. 

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? 

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

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? 

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

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

There are 5 birds. 2 are on the fence. How many are not on the fence?

This lesson will soon be taken down.

Understand subtraction as decreasing an amount

Lesson outcome