Question 1134110
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Each of the 7 teams plays games against the 6 other teams.  Counting all those games counts each game twice, because each game involves 2 teams.<br>
So the number of games is (7*6)/2 = 21.<br>
For a more formal mathematical approach to the problem, recognize that each game is a result of choosing 2 of the 7 teams in the tournament.  And "7 choose 2" is<br>
{{{(7*6)/(2*1) = 21}}}