Working with the metric system really takes off in Year 3 (7/8 years old). During this year children are expected to know that:
1 kilometre = 1,000 metres
1 metre = 100 centimetres
1 kilogram = 1,000 grams
1 litre = 1,000 millilitres
They are also expected to recognise half units, such as half a kilometre and that this can be written as ½ km, or 0.5 km or 500 m.
One of the most useful benefits of the metric system is the relationship between the units:
a litre of water can be contained in a 10 cm cube (1,000 cubic cm) and has a mass of approximately 1 kg (depending on temperature). Hence a 1 cm cube of water has a mass of approximately 1 gram and is known as 1 ml.
Whilst children should be working with practical apparatus (measuring jugs, rulers, weights etc.) they are also expected to begin to solve word problems. Our latest set of pages looks at finding the total distances of routes marked in kilometres using one decimal place (eg 3.4 km).