Children learn to calculate the area of rectangles in cm² and m², and work backwards from the area to find an unknown side length.
In Year 5, children calculate and compare the area of rectangles and squares using standard units, specifically square centimetres (cm²) and square metres (m²). They multiply the length by the width to determine the total space inside a shape. Children also use short division to reverse this calculation: using a known area and one given side to deduce the missing length of another side.
A frequent mistake is mixing up area and perimeter. Pupils often add the side lengths together instead of multiplying them, or label their final answer with standard units like cm rather than square units like cm². When finding an unknown side, children also commonly try to multiply the area by the known measurement instead of dividing the area by that side.
Worksheet tasks build this skill step by step. With Area of a rectangle, children calculate the area from labelled diagrams, while Area of a rectangle in everyday life applies these calculations to real-world contexts such as garden plots or tabletop measurements. In Missing side of a rectangle tasks, children are presented with the total area alongside one dimension and must divide to find the missing edge.