There are 10 teams in a football league.
Two teams are going to be chosen at random to play a match.
Work out the number of different matches that could take place.
Hence, work out the number of different matches that could take place if there are n n\,n teams in the football league.
181 exam-style questions on OCR GCSE Maths The Product Rule for Counting. Each one has a worked solution and a mark scheme showing where the marks go.