1. You threw a strike, which is 10 plus your next two shots. In this case, your next two shots (the second frame) resulted in a spare. 10+10=20.
2. You threw a spare, which is 10 plus your next shot. Your next shot (from the third frame) was a 7. The value of this frame is 17 (10+7). Added to the first frame, you're now at 37.
3. An open frame is worth exactly the number of pins you knocked down. 7+2=9. Added to 37, you're now at 46.
4. Another spare. Adding your next shot (from the fifth frame-a strike), you get 20 (10+10). Added to 46, you're at 66.
5. A strike, followed by two more strikes. 10+10+10=30, putting you at 96.
6. A strike, followed by a strike and a 2. 10+10+2=22. You're now at 118.
7. A strike, followed by a 2 and 3. 10+2+3=15, putting your score at 133.
8. An open frame. 2+3=5. You're now at 138.
9. A spare, followed by a 7 in the tenth frame. 10+7=17, putting you at 155.
10. A spare, followed by a 3. 10+3=13, resulting in a total score of 168.
The Tenth Frame
In the sample score, three shots were thrown in the tenth frame. This is because of the bonuses awarded for strikes and spares. If you throw a strike on your first ball in the tenth frame, you need two more shots to determine the total value of the strike.
If you throw a spare on your first two balls in the tenth frame, you need one more shot to determine the total value of the spare. This is called a fill ball.
If you throw an open frame in the tenth frame, you won't get a third shot. The only reason the third shot exists is to determine the full value of a strike or spare.