Children are introduced to millimetres in Year 3 and they will understand that millimetres can be used to measure lengths that are not an exact number of centimetres. Measurement should be recorded as a number of centimetres and millimetres e.g. ‘the pencil is 6 cm and 4 mm long’.

Children are expected to know certain facts, including:

*1 metre = 100 centimetres*

*1 centimetre = 10 millimetres*

Many children find the millimetre difficult to use and when drawing lines accuracy to within 2 mm is fine.

It is, of course, important that they have rulers and tape measures which include millimetres and that they can measure along the top edge from left to right. (Watch out for rulers and tape measures that still have inches on the top and centimetres below.)

Perimeter is also introduced in Year 3. It is taught as the distance round the outside of an enclosed shape. This can be done in a practical way, such as walking round the outside of a grid marked on the playground. On paper, squared paper is often used, but it is important not to confuse area with perimeter.

Our worksheets clearly show the progress that needs to be made between Year 2 and Year 3. We have an excellent collection of work covering all aspects of measuring length so have a look now.