This week, we have started our new unit on ‘Length and Perimeter’. In previous years, children measured lengths using metres (m) and centimetres (cm).
They have now been introduced to kilometres and the abbreviation ‘km’. The children used the fact that 1 km is equal to 1,000 m to derive related facts using numbers up to 10,000. The children explored perimeter focussing on calculating the perimeter of rectangles using the side lengths, rather than counting the squares.
This work was developed further by calculating the perimeter of rectilinear shapes, where all sides meet at right angles. The children were taught that when calculating perimeter they should mark the sides they have already counted to avoid duplication or omission.