The note
How schools teach it now
Children sort shapes by properties: sides, angles, parallel and perpendicular lines, lines of symmetry; for 3D shapes, faces, edges and vertices (corners). A square is a special rectangle, and a rhombus (not a 'diamond') is a special parallelogram.
5-minute kitchen-table activity
Raid the recycling: a cereal box (cuboid), a tin (cylinder), a chocolate box shaped like a tent (triangular prism). Count the faces, edges and vertices on each. Which has the most?
Worked example
How many edges does a triangular prism have?
- Two triangle ends with 3 edges each: 6 edges.
- Three more edges join the two ends.
- 6 + 3 = 9.
Answer: 9
Common mistakes to watch for
- Thinking a square isn't a rectangle (it is, a special one).
- Mixing up faces, edges and vertices.
- Calling a rhombus a 'diamond' in a written answer.
Encouragement
- Try saying
- “What do you notice about its sides and corners?”
- Rather than
- “Shapes are easy, you should get these.”