l need these letters but l forgot them l need them can someone help me please!!!!!!!!!!!!!!

What in the name of all that is holy are you talking about?

Do you mean the letters that go after the rating.like 5.10a (for example)?

If that is the case, the letters are a way of further defining the difficulty of the route, within some of the rating system ( l just used the YDS as an example).

See the link below for an explanation of the myriads of climb rating systems.

If u r asking about ratings the two standards r the V-scale & YDS. YDS is the more general / widely used indoors (and outdoors as well). For technical climbing purposes, it starts at 5.1 & goes to ~5.15 (though it is open-ended). 5.1 is a climb that would be almost impossible to fall on, but is steep enough that u would be seriously injured or killed in an unrestrained fall. 5.15 is roughly equivalent to climbing a vertical pane of greased glass.

You r probably asking about the letter distinctions. The scale goes 5.1, 5.2, 5.3 .. 5.8, 5.9, 5.10a, 5.10b, 5.10c, 5.10d, 5.11a.. this is because it was originally intended to stop at level 5.10, but with modern advances in climbing equipment it now goes much further. In theory it is linear, i.e. going from a 5.10b -> 5.10c is the same change in difficulty as going from a 5.7 -> 5.8.

l agree with those above, except for the greased glass part!! LOL!! l think that is more like a 5.16.a..