Just because you're great at everything else doesn't mean you'll be good at one thing. In this case Rin just flat-out suck at bowling, ESPECIALLY comapared to Len.
greengale said: How many points is a strike, anyway?
I think it's ten, then the next two balls' pins struck are added to the strike frame. So Strike, then 3 and 4 would be (10+3+4) and (3+4) making 24 for two frames. It obviously starts stacking up if you get multiple strikes.
greengale said: How many points is a strike, anyway?
10, to a maxim of 30. The rest as said by JakeBob.
The basic scoring in bowling is thus: Each pin counts as 1 point, A Strike gains the points of the next two, a Spare gains off the next. If the 10th frame is a strike, then two attachment frmaes are added to decide the score, a spare naturally adds one. Of 10 frames it's only possible to get 300 points, that's considered a perfect game. I actually knew someone who did this.