To calculate the total number of matches played in a league with 18 football teams, you can use the formula n(n-1)/2, where n is the number of teams.
1. Substitute the number of teams (n=18) into the formula:
Total matches = 18(18-1)/2
Total matches = 18(17)/2
Total matches = 306/2
Total matches = 153
Therefore, in a league with 18 teams, the total number of matches played would be 153. Each team plays two matches against every other team, resulting in a total of 153 matches in the league.