Significant figures

Home learning focus

In today's lesson, you will learn about significant figures and how to estimate.

This lesson includes:

  • a learning summary
  • two videos
  • two activities

Created in partnership with Sparx.

Learn

Significant figures show how important each digit in a number is when you want to know its size.

Significant figures - integers

For integers, identify the significant figures from left to right.

When rounding a number to a significant figure, you end up with an approximate value for the number. This can be useful when estimating the answers to difficult calculations.

Now, watch this video from Sparx to find out how to round integers to a given significant figure.

Rounding integers using significant figures

Significant figures - decimals

Rounding decimals to a given significant figure is very similar to rounding integers, but there is one important difference.

For decimals, leading zeros are not significant.

Watch this video from Sparx to find out how to round decimals to one or two significant figures.

Rounding decimals using significant figures

Practise

Activity 1

Significant figures - Integers

Have a go at this worksheet from Sparx on rounding integers to one or two significant figures. You can print it out or write your answers on a piece of paper.

Significant figures - integers

Activity 2

Significant figures - Decimals

Have a go at this worksheet from Sparx on rounding decimals to one or two significant figures. You can print it out or write your answers on a piece of paper.

Significant figures - decimals

There's more to learn

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

KS3 Maths
BBC Bitesize Daily
The BBC Bitesize 14 day sort-your-life-out challenge
11 - 14 Maths
Bitesize Careers
Britannica Digital Learning