In tennis, the scoring system is unique.
Each game starts at “love,” which means zero.
The first point is called “15,” the second is “30,” the third is “40,” and the fourth point wins the game.
If both players reach 40, it’s called “deuce,” and a player must win two consecutive points to win the game.
Matches are usually played in sets, where you need to win at least six games by a margin of two games.