### Construct-o-straws

Make a cube out of straws and have a go at this practical challenge.

### Matchsticks

Reasoning about the number of matches needed to build squares that share their sides.

How can the same pieces of the tangram make this bowl before and after it was chipped? Use the interactivity to try and work out what is going on!

# Face Painting

### Why do this problem?

This problem is a good way to explore properties of the Platonic solids and gives children opportunities to visualise 3D shapes.

### Possible approach

You might like to get children making their own Platonic solids using sheets of paper before trying this activity. This article shows you how to go about it.

Alternatively (or in addition) it would be useful to have some Polydron available for children to build their own solids as they work.

You could introduce the problem by asking children to visualise the cube, asking for justifications of the minimum number of colours needed before they are able to physically make it to check.

### Key questions

How many faces/edges/vertices does this shape have?
How many other faces does each face touch?