There are myriad ways to do this, the most comprehensive being the area code method. 1-10 on face, binary on bangability, 1-10 on body. So, a butterface with a smokin' body would be a 209, but a cute girl with some weird stuff happening elsewhere might be a 715. Nobody really uses it, though, because they can never remember what the first digit and last digits represent.
My friends and I dispensed with all the mathematics awhile ago and, true to guy nature, just started doing the 0-1 scale.
Hahahahahaha. Yes it's so so very true. How did you know? Girls aren't supposed to know this stuff. That's why it's guy code talk. There is also a scale where you just say yes or no on whether you would f*** her or not
lol. a massive range of ways. There's the standard 1-10. Or the reverse 1-10; regarding how many beers it would take. Personally I use the "hell yeah", "wouldn't say no" (ie I wouldn't chase her, but if she made a move I'd go with it), "eewww" etc. Gives you a chance to really express yourself :)