Question

there is 51 students in the gym class and they are picking captains and there is one left and the teams have to be even so where does the last one go

Answer 1

How many captains are picked? For how many teams?

How can there be only one left if they are picking captains? Is everyone a captain?

If there really is one left over, that odd one out can umpire or run laps around the track.