I can never get my head around using the term 2/1 chance or 3 to 1 or whatever. I want to know my percent chance to win. I can understand better. I've memorized mosts odds that way. All in approximates
P over P = 80/20, Any Ace over a P = 30/70 KJ over 99 = 47/53 or coin flip, A6 over K8 =60/40

But when someone says well I was 5.5 to 1 to win I'm like, ok whats that mean. I was discussing this with friends and a way for me to think over the easy ones was to quickly turn it into a percent but they told me my math was wrong. For example I always thought of totaling them to 100 to make my percent. 2/1 being like 66/33. If I'm 2/1 to win I have a 33% chance to win. Like a oesd is 32% or 2/1.

The big discussion with my friends I think was with a flush draw on the turn. I know a flush draw is 20% on the turn. So to reverse it I think it is 4 to 1 making 100. They told me 20% is 5 to 1 because you have a 1 in 5 chance of hitting it. But I always add the two together to get the total being 100%

Which one is correct? I could go rip open The Theory of poker but it's late right now and I need to go to bed.

It's just converting a % to a fraction.

50% chance. You will win once, you will lose once. Hence a 1 to 1 chance.

33%, You win once, you lose twice, hence a 2 to 1 chance.

7 - 2. twice you win, seven times you lose, so your 2/9, or about 22%

When your a X - Y chance, Take X or Y (Whichever applies to you) and divide it by X+Y.

If you are a 5-2 dog, then you have 2/7 chance of winning, or about 28%.