请问 数学统计C(m,n)的通用计算公式是

Fanzi316316

If each of the 12 teams participating in a certain tournament plays exactly one game with each of the other teams, how many games will be played? 看结果解析是C(12,2)=(12*11)/（2*1）=66。请问 C(m,n)的通用计算公式是？谢谢啦