First of all, thank you for your quick help.
Well, I guess "system" wasn't the right term. But for me as freeformer everything using a dice is kinda 'stem'. Sorry about that.
Concider me eccentric, but it doesn't feel completely like fate to me when I say "1-10: I get busted, 11-100: I get away"...that's why I am looking for a 'system'.
Let's say something where I choose the likeliness (very likely - very unlikely) than and get my 'yes' or 'no' without getting to see all the "maths".
It may sound stupid, but at some point in my life I have chosen letters over numbers and now I'm trying to avoid numbers as good as I can (in case they're mad at me)
But don't trouble yourself, guys. If someone happens to know something like that, great...if not - meh - I think I'll survive