if you want to convert your outs to percentages, for eg. youve got 9,10 unsuited and 7,8,A rainbow flop comes you've got an open ended straightdraw, the four Jacks and four 6's will complete your hand. it would be fair to say someone has the ace for this e.g so hitting a 9 or 10 wont be added as outs so in total you have 8 outs to this open ended straight. to complete it by the turn you multiply by 4.

so you have 4 * 8 = 32% of getting there if its a miss you multiply your outs by 2 by giving us by the river only 16% chance of connecting the board for us.

if you want your pot odds, its the total pot over to what you need to call to stay in the pot... e.g the pot contains 1200 in chips and the play before you raises 400 making a total of 1600. you are being asked to call 400 for 1600 chips. to turn it to odd its 1600/400
thus giving us 4/1 pot odds not a bad call at all id say..... depends on your outs as well.

using the previous e.g having 32% on the turn its a good call as the pot odds get involved. to work out what percentage you need to being whats being asked to call youve got 4 to 1. add these together you get 5 divide 100 by 5 you get 20%. the pot says you need a minimum 20% to continue but you have 32% making this a correct call.

if this e.g was on the river youre now on got 16% but the pot is saying you need 20% making it incorrect to call, but you can negate this with your implied odds usally as its quite a marginal call. over time it becomes quite natural thinking.

hope the maths helps ya