A game of tenpin bowling consists of 10 frames, with a maximum of two balls bowled per frame.
If any pins are standing after you have bowled your two balls, simply count the number of pins you have knocked down. If there are two pins standing, for example, your score for the frame is eight and would be marked on the score sheet as shown (Figure A).
Scoring gets quite a bit more complicated if you knock down all the pins. If you do this on the first ball, it's a strike. You smugly take a seat and record an X on your score sheet as shown (Figure B). A strike is worth the 10 pins you knocked down plus a bonus: the number of pins you knock down with the next two balls (bowled in the next frame or--if you get another strike--the next two). For example, if you throw a strike and then next frame knock down a total of nine pins on two balls, your score for the first frame is 19, your score for the second is nine, and your total for the two frames is 28. A strike in the tenth frame allows you to bowl two additional balls.
If you knock down all 10 pins with two balls, it's a spare, which is marked on the score sheet with a slash mark (/) as shown (Figure C). A spare is worth 10 pins plus the number of pins felled next frame by your first ball. So if you throw a spare, then next frame knock down seven, then two, your score for the first frame is 17. Your score for the second is nine, and your total is 26.
