New multiple of 10 rolling system

[Dr.Orpheus]

Over the holidays I discovered a way to make variations of the d% and made a rolling system out of it (see spoiler). It can even be expanded by adding a third die into the mix. This would take some getting use to like learning a game with a die pool after only playing D&D, but it does not seem too hard.

What are your thoughts? Is this concept already used in an RPG system I don't know of? What type of game might this be useful for, or is it unnecessarily complicated?

Spoiler: Rolling System

Show

Desired Range	Tens Place	Ones Place
1-10	-	1d10
1-20	-	1d20
1-30	1d3	1d10
1-40	1d4	1d10
1-50	1d4	1d20
1-60	1d6	1d10
1-70	1d6	1d20
1-80	1d8	1d10
1-90	1d8	1d20
1-100	1d10	1d10
1-110	1d10	1d20
1-120	1d12	1d10
1-130	1d12	1d20

[Knaight]

I've seen this crop up every so often for tables, but not much else. It's an established mechanic, just not one that sees a lot of use.

[Pleh]

Yeah, I think I just don't care about setting up a 1 in 60 chance of something. By the time I need to be that specific, I can roll percentile and accept values 1-60 and throw out 61-100. I would need a system that actually uses these other number ranges frequently to justify the mechanic

[John Campbell]

This doesn't actually provide even distributions for anything that uses two dice and includes the d20. Rolling 1d6*10 + 1d20 as a d70, for example, gives only one way to roll 1*–10 or 61–70, but two ways to roll 11–60, so numbers in the 11–60 range will come up twice as often. If you don't have a d7, to get an even 1–70 distribution, you need to roll 1d8*10 + 1d10 and reroll 8s on the d8.

You can get different ranges with even distributions by using different die types, but you have to make your high-die multiplier be the size of the low die. For example, 1d6*20 + 1d20 will give you a even distribution over 1–120 (though it's easier to just use 1d12*10 + 1d10). The low die doesn't have to be a multiple of 10, either. You can, for example, roll 1d4*8 + 1d8 and get an even distribution from 1–32... better than 1d30 for random days of the month.

(In all cases, of course, you treat max values on the dice as zeros, unless you roll them on both dice, then it's top of range.)

Or, y'know, just do what I do when I need a random number in a weird range. Ask a computer. They don't care if you can do it by manipulating platonic solids or not. Need a d31? Not a problem!