Estimation means to find a value that is close enough to the right answer, usually with some thought or calculation involved.

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

Use knowledge of column addition to solve problems in a range of contexts

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

Each of Enzo the elephant’s tusks are 315 cm long. Which would be the most accurate estimate for the length of both of his tusks? 

Each of Enzo the elephant’s tusks are 315 cm long. What is the total length of both of his tusks? {{ }} cm. 

Eddie the elephant is 347 cm tall. With his trunk, he can reach an extra 148 cm upwards. How far can he reach altogether? Eddie can reach {{ }} cm.

Which calculation is the best one to estimate the sum of 459 + 289? 

Look carefully at Alex’s column addition. Which of these statements about the sum is true? 

Eva and baby Elliott have a total length of 585 cm. Choose the correct lengths for Eva and her baby. 

Where will regrouping be needed in this column addition? 

What is the missing digit in this column addition? 

What would be a good estimate for the sum of 189 + 217? 

Which of these calculations would it be more efficient to calculate mentally?

Which pairs of addends give a sum between 500 and 600? 

This lesson will soon be taken down.

Use knowledge of column addition to solve problems in a range of contexts

Lesson outcome