Why do this problem?

This problem offers a good opportunity for students to work systematically.

Possible approach

This is a good starter question to have on the board as students enter the room.

Key questions

• What numbers might go next to the 12?
• How many ways of putting the numbers on the clock might there be?

Possible extension

• Can the numbers 1 - 13 be arranged in a circle so that the pairs add up to a triangle number?

Possible support

The