Help

[Prince]

Can anyone help me,
We know Round robin of N players has N(N-1)/2.
Exm. 8*(8-1)/2= 28 matchs
We know Double Round robin of N players has N(N-1)
Exam. 8*(8-1)= 56 matchs
But my question, what is for group stages??

[Ian Wakeling]

Is it not the same calculation within each group?  For example in the FIFA World Cup there are 8 groups (G) of 4 teams (M), so there are G*M*(M-1)/2 = 48 group matches for their single round-robin format.   Or have I not understood the question correctly?