Thank you OD, this man seems not to understand that sometimes in math you must multiply instead of add and subtract.
You get paid out as if there was 36 numbers on all bets in roulette, if you do the math, you end up with the same house edge no matter what - volatility is just a measure of risk.
If you 1 dollar bet on all of the the 18 black numbers, you'd get paid the same for a win as if you put 18 dollars on black itself, revealing that the HOUSE EDGE IS THE SAME between putting a bet on the individual numbers and on even money buts UNLESS there is an Em Prison rule.
The edge is very easy to caculate, it's 1-(36/38) which equals .0526/5.26% on all bets except (0,00,1,2,3) which is a suckers bet. For European roulette it is 1-(37/38) which gives an edge exactly half of that, which is 2.63%. With an Em Prison rule Even Money bet's house edge is approcixametly half of that, or 1.35ish%, unless the rule is for another spin to resolve it, in which case it's only slightly higher.
This is basic math - probability you should have learned in middle school.
I've got a feeling your studying of roulette has involved a whole lotta systems which, if they worked, people would be playing them instead of selling them but whatever.
The only roulette systems that have worked are tracking number biases and people have been documented making buttloads of money until the casinos figured out what was going on and banned them. See what happened - they never sold their system, they played until they were banned because they were making ridiculous money, they didn't sell their system because casinos would adjust their games if their system got out.