### Cubes

Investigate the number of faces you can see when you arrange three cubes in different ways.

### Pebbles

Place four pebbles on the sand in the form of a square. Keep adding as few pebbles as necessary to double the area. How many extra pebbles are added each time?

### Bracelets

Investigate the different shaped bracelets you could make from 18 different spherical beads. How do they compare if you use 24 beads?

# Two Primes Make One Square

##### Age 7 to 11 Challenge Level:

Try with the squares of the numbers between $4$ and $20$.

Did you find any square numbers which cannot be made by adding two prime numbers together?