Column subtraction is a way of subtracting numbers by writing a number below another.

The process of unitising and exchanging between place values is known as regrouping.

Subtract from a 3-digit number using column subtraction with regrouping

Maths

In this unit pupils will identify the minuend and the subtrahend in column subtraction and explain the column subtraction algorithm They will subtract from a 2-digit number using column subtraction with exchanging In the future unit pupils will use their knowledge of column addition column subtraction with exchanging to solve problems They will evaluate the efficiency of strategies for subtraction

In the prior unit pupils identified the addends and the sum in column addition. They used their knowledge of place value to correctly lay out column addition. In this unit pupils will identify the minuend and the subtrahend in column subtraction and explain the column subtraction algorithm. They will subtract from a 2-digit number using column subtraction with exchanging.

Column subtraction

Where is regrouping needed in the column subtraction? 

Finish the column subtraction. What is the difference?

A ten has been regrouped into 10 ones. What number is represented by the base ten blocks?

In which of these calculations would you need to regroup? 

This lesson will soon be taken down.

Subtract from a 3-digit number using column subtraction with regrouping

Lesson outcome