This is a relay race on mixed percentages used with my Y9 group but also with my GCSE groups. I suggest printing and laminating 8 sets and getting them to work in groups of 4. They all start on question 1 and then they come up for the next questions when they have the answer to the last.
After half way through I change the rules so they have to split into pairs and take turns answering the groups questions.
I had an hour lesson and even the highest ability only reached question 12/14.