# Efficient addition and subtraction methods

## Home learning focus

In this lesson, you will learn efficient methods for adding and subtracting from 4-digit numbers.

The lesson includes:

• two videos
• two activities

Created in partnership with Pearson.

# Learn

These activities will teach you written methods for addition and subtraction, often called ‘column methods’.

However, sometimes it makes more sense to solve some additions and subtractions using a mental method.

The problems in this lesson all involve adding or subtracting multiples of ten, and the numbers are chosen carefully so that you can use a mental method to solve them.

You will learn how to look at a calculation and decide on the most efficient strategy to find the solution, rather than always reverting to a written method.

For example, to solve 700 – 1, it is more efficient to count back one than to write a full column subtraction!

### Efficient addition and subtraction methods – Part a

In this video, learn to add hundreds to a 4-digit number using an efficient mental method.

### Efficient addition and subtraction methods – Part b

In this video, learn to use efficient methods to add 1s, 10s and 1000s to a 4-digit number.

# Practise

## Activity 1

This worksheet will help you practise adding and subtracting using efficient methods. Remember to think about what is changing in each calculation – the 1s, 10s, 100s or 1,000s?

## Activity 2

These problems all involve the same new skill, but they are applied in slightly different contexts. Look out for missing number problems!

# There's more to learn...

Have a look at these other resources around the BBC and the web.