There's no getting away from it, tennis has an unusual scoring system.
The score does not go up in units of one or even in units of the same amount.
The first point in a game is called 15 and the next 30. So you'd think that the next point should be 45 - but it isn't, it's 40.
And the score of a player who has not won any points is not 'nil' or 'zero', but 'love'.
This is said to come from the French word 'oeuf', which means "egg" and is shaped like a zero.
The server's score is always called first by the umpire.
So if Player A is serving to Player B and Player B wins the point, the score is love-15.
If Player A wins the next point the score is 15-all, and so on.