*** once you've understood today's learning, you can test your calculator skills by using your calculator to check your answers and/or doing some of the harder questions
Imperial measures are the 'old versions' of measures like feet, inches miles and pints.
We sometimes still use these but a lot more often we use the metric words and measures like litres, metres and kilometres.
The reason these measures change over time is because it is easier to convert metric measures - just multiply or divide by 10, 100 and 1000.
For the imperial measures it is a lot more complex to convert them.