Skip to main content
### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### For younger learners

### Advanced mathematics

# Skeleton Shapes

## Skeleton Shapes

**Why do this problem?**

### Possible approach

### Key questions

### Possible extension

### Possible support

Or search by topic

Age 5 to 7

Challenge Level

- Problem
- Getting Started
- Student Solutions
- Teachers' Resources

Skeleton shapes are made with balls of modelling clay and straws.

This shows a cube and a skeleton cube:

How many balls of modelling clay and how many straws does it take to make the cube?

Here are some piles of modelling clay balls and straws:

Look at the shapes below and decide which piles are needed to make a skeleton of each shape.

How do you know which piles go with which shape?

This problem helps children begin to become familiar with the various properties of common geometric solid shapes, concentrating on edges and vertices. It also helps in promoting discussion and experimentation. Naming the shapes should be a help during discussion and description of what has been done, rather than being an exercise in its own right.

Before doing this problem children should have had plenty of free play building with sets of solid shapes so that they begin to get a feel for their properties. They should also have chance to experiment with building skeleton shapes either with a specific kit or with drinking straws and modelling clay/plasticine.

You could start on the problem by asking the group to tell you what they know about cubes. Using a large cube, ask them to count the faces, the edges and the vertices (corners). (Avoid the word "side" which can be confusing when discussing 3D shapes and use instead "face" and "edge".)

After this you could encourage the group to work in pairs on the problem from a printed sheet so that they are able to talk through their ideas with a partner. It is essential that children have real 3D shapes to handle and count as they work and if at all possible they should have opportunity to experiment by making skeleton shapes as
well. This sheet might be useful for recording for those children who would find making their own table for results difficult.

How many edges did you count? What does this tell you about the number of straws we need?

How many corners did you count? What does this tell you about the number of balls of modelling clay we need?

How many edges meet at this corner?

Children could find other solid shapes and continue the activity. They could also record by drawing the shapes they have used on isometric paper although this is rather tricky!

Start by counting the faces on a cube - a large dice might be useful - and then the edges and finally the vertices. A non-permanent pen could be used to mark a real shape if children are having difficulty keeping track of their counting.