M3.5.8 For the adult
Solids, nets and views
A cube has 6 faces, 8 corners and 12 edges. Is there a rule that links the three numbers?
What this chapter teaches
A cube is drawn on isometric dotted paper with lines that go up, up to the right and up to the left. A solid has faces, edges and corners, and faces + corners − edges = 2 for solids with flat faces and no hole through them. A net is a flat shape that folds up into a solid, and a view is the flat shape seen from one side.
Three questions to ask
There is no one right wording. Listen for the idea.
- How many faces, corners and edges has a cube, and what does faces + corners − edges give?
- Why does a cube on dotted paper show only 9 of its 12 edges?
- How can you tell whether six squares joined together fold into a cube?
After the chapter, the learner can
- Draw a cube on dotted paper
- Draw a solid as seen from the front, the side and the top
- Check that faces + corners − edges = 2 for a solid
What they copy into their notebook
A solid has faces, edges and corners. Faces + corners − edges = 2. A net folds into a solid. A view is the flat shape you see from the front, side or top.