Measures and accuracy Revision Notes

Common unit conversions

Mass: 1 kilogram (kg) = 1000 grams (g). Length: 1 metre (m) = 100 centimetres (cm), and 1 kilometre (km) = 1000 metres. Money: £1 = 100 pence (p). Time: 1 hour = 60 minutes and 1 minute = 60 seconds.

Decimals in measures

To convert kilograms to grams, multiply by 1000; to convert metres to centimetres, multiply by 100. A decimal part of an hour is a fraction of 60 minutes: 0.25 hours is 15 minutes, 0.5 hours is 30 minutes and 0.75 hours is 45 minutes.

Compound measures

A compound measure uses more than one unit, such as speed in kilometres per hour or metres per second. For speed, divide distance by time when the distance and time units match the required answer units. Check that the final answer includes the compound unit.