The dart rules of TacTics

Goal: Hit the number 10 to 20 and Bull three times.
When you hit a number more than 3 times, and your opponent has not yet hit this number three times, you can score points.

Most people write the score for TacTics the following way:

Your Score
X   X (value is hit two times)

Score opponent
X     (value hit 1 time)

When you hit a triple and a single you have four times twenty.
You need one twenty to get the number closed.
Now you have 3 times twenty left (4-1).

Because your opponent has not yet hit the number 3 times you get points.

You get, when the value is for instance 20, 3 times 20 points (=60 points total).

The player with the most points and the numbers 10 to 20 and bull hit 3 times wins the game.