What is the tennis score when the server has won 4 points and the receiver has won 3 points?

When the server has won 4 points and the receiver has won 3 points, the appropriate tennis score is "Ad-in." In tennis, the scoring system transitions through several stages: 0 (love), 15, 30, 40, and then to "game" if the player wins a point after reaching 40. If both players have won 3 points each, the score is at deuce.

Once a player wins a point from deuce, they reach "advantage." The term "Ad-in" indicates that the server has the advantage, which happens when they win a point after deuce. The score would then be declared as "Advantage in" for the server, which is commonly abbreviated as "Ad-in." If the server loses the subsequent point, the score would return to deuce. If the server wins another point while at Ad-in, they win the game.

In this case, with 4 points for the server and 3 points for the receiver, being one point ahead of the receiver results in the server being at an advantage, thus correctly identified as Ad-in.