A hands-on Year 3 maths lesson introducing perimeter as the distance all the way around a shape. Children measure real classroom objects, add sides carefully, learn the rectangle doubling shortcut and the square multiply-by-4 trick, and solve a missing-side mystery by working backwards. It is a ready-to-teach PowerPoint scaffold for an hour-long lesson on perimeter, with a ruler-based Classroom Perimeter Hunt and a Design the Dragon’s Garden challenge on squared paper. Common pitfalls, worked examples and a quiz are all built in.