Perimeter and Area - Perimeter on a Grid - Planning

Year 5 students embark on a journey through measurement, focusing on the concept of perimeter within the first week of their Autumn term. The lesson aims to equip students with the ability to calculate the perimeter of rectilinear shapes using grid paper. Rectilinear shapes, defined by their right-angled corners, form the basis of the lesson's practical activities. The class begins with a discussion to refresh their understanding of what perimeter means, emphasising that it is the total length around a shape. They are then presented with grid-based activities where they count squares to determine the lengths of sides, applying their knowledge to avoid counting each square individually. For example, they learn to calculate the perimeter by adding the lengths of matching sides or by using multiplication for pairs of equal sides, such as (4 x 2) + (3 x 2).

Further activities challenge the children to consider more complex shapes, where they must account for additional sides, and to draw shapes with identical perimeters using cubes or sticks for a hands-on experience. The lesson also prompts them to think about real-world applications of perimeter, such as the dimensions of a football pitch. To consolidate learning, differentiated worksheets are provided, allowing students to practice with shapes of varying complexity. Throughout the lesson, key questions encourage critical thinking about perimeter and rectilinear shapes, while a reflective 'Give me five' plenary helps students to identify what they have learned, the skills they've used, and any aspects they found challenging. Misconceptions are addressed, such as the incorrect belief that all four side measurements are needed to calculate perimeter or that the inside of the shape should be counted rather than the lengths of the edges.