A cycle is two games, for example, a league is 20 teams, then their league is usually a single cycle. That is, any two teams have to play twice. 20 teams will have 38 rounds (because they can't beat themselves, it's 20 minus 1 multiplied by 2).

The general European leagues are single-cycle, that is, one game is played at home and one game is played at away.

But there are exceptions For example, in the Scottish League, they only have 10 teams.

So to play double round robin, different teams have to play four games, two home games and two away games each.

For example, the team of 10 is 36 rounds.