L24 – WWW – Decompose Shapes

Working Without Worksheets – Reception Maths: Decomposing Shapes Help your Reception pupils build spatial reasoning with this Working Without Worksheets lesson on decomposing shapes . Building on the previous lesson about composing shapes, children now explore how larger shapes can be split into smaller ones. Using tangrams, playdough, and shape cutters, they learn that a single shape can be divided in different ways while keeping its properties. The lesson begins with a starter activity : Show a square and ask: “Can you see any smaller shapes inside the square?” Model cutting the square into 2 rectangles, then into 2 triangles. Emphasise that the square is still made up of shapes that have their own properties. In the main input , children explore tangrams: Show a square tangram and explain that the large square has been split into many smaller shapes. Ask: “What shapes can you see in the square?” Examine the shapes in turn. Point out that there are 5 triangles —all have 3 sides, but they appear in different orientations and sizes. Discuss how decomposing a shape helps us see both parts and wholes. For the independent activity , children explore decomposition hands-on: Playdough Decomposition – children cut out a square, rectangle, or triangle from playdough. They then use a tool to cut the shape into 2, 3, or 4 smaller shapes. Encourage them to describe what they made: “I cut a square into 2 triangles” or “I cut a rectangle into 3 smaller rectangles.” Discuss whether the new shapes are the same or different. The plenary consolidates learning: Bring the class together to look at examples of decomposed shapes. Reinforce that a whole shape can be split into parts in many ways. Link back to composing shapes: shapes can join together and also split apart. What’s Included in the Pack? ✔ Full teacher planning with objectives, vocabulary, and plenary questions ✔ Starter: explore smaller shapes inside a square by cutting it into parts ✔ Teacher modelling: use a tangram to