This was developed by Liverpool Mathematical Society and consists of sets of practical mathematical activities. Pupils work in pairs and complete as many of the activities as they can in the time. The guiding principal is that participants should, at times, meet mathematics in a non-confrontational way in which all succeed, the keywords being enjoyment and challenge. Fun maths is 'all ability' in the sense that some activities are easy whereas others are more challenging, some are logic based, some based on spatial awareness and some on trial and improvement.
There are some challenges I can only complete with my copy of the solutions, but some students find them a doddle! Much more fun and challenging than the description above leads one to believe!