How many elbows?
I’ve been playing a fun game with my YLs recently which I picked up at summer school. It’s great fun and gets them thinking. Get all the students standing up and then say they need to get into groups with seventeen fingers or three elbows or six noses or seven eyes or any number of body parts you like. It encourages them to work together as they try and make up the correct number and it’s great fun too!