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.

Review using column subtraction with regrouping from hundreds to tens

Maths

In this unit pupils will revisit column addition with regrouping and column subtraction with exchanging to solve problems. They will read Roman numerals to 100. In the future unit pupils will consolidate column addition with regrouping and column subtraction with exchanging to solve problems. They will use known facts and strategies to accurately and efficiently calculate and check.

In the prior unit pupils identified the minuend and the subtrahend in column subtraction and explained the column subtraction algorithm. They subtracted from a 2-digit number using column subtraction with exchanging. In this unit pupils will revisit column addition with regrouping and column subtraction with exchanging to solve problems. They will read Roman numerals to 100.

Review of column addition and subtraction

Regrouping is needed in the ones and tens. 

Where is regrouping needed in this column subtraction?

Complete the column subtraction. What is the difference between the two numbers? 

Which calculations need regrouping from the tens to the ones? 

Complete the column subtraction. What is the difference between the two numbers?

Find the missing difference in the column subtraction.  

Find the missing ones digit in the column subtraction.   

This lesson will soon be taken down.

Review using column subtraction with regrouping from hundreds to tens

Lesson outcome