Quote Originally Posted by RiverMonkey

p = pot odds = current (or effective) pot size/amount to call
n = number of unseen cards = 47 on flop, 46 on turn
o = number of clean and/or partial and/or hidden outs

'Backwards Method':
I like this one best for at the table ...

if o*(p+1) > n you should call

or, p*o > n-o
Im confused with the above.

Very simplifed example: $20 pot, $5 to you to call.

You are 4 to a flush after flop.

Using the above: o=9, n=47, p=4
9*(4+1) = 45 isnt greater than 47, so fold
or
4*9 is not greater than 47-9 so fold

Now, comparing this to my original way of thinking through the above.

pot odds: 20/5 = 4 - You need to win this hand 1 in 5 times to break even, or 20% of the time.

hand odds: 9 outs = 1.86 to 1 - You will win this hand once in approx 3 times played, or approx 34% by the river.

By the above calculations, this would be a call. Where did I go wrong?