according to the outs/odds chart in the articles, you see that if you have 13 outs , your odds are based on 2 cards 1:1

This does NOT mean that you win 100% but you lose 1 and you win 1. Meaning a 50% chance of winning.

Now this is with numerators. you can say I have odds against of 1:1 but you also can say I have a winning chance of 1/2 or 50%

Now with other situations (against) you just add up the lonely 1 to your odds against and then you do that number to the power of minus-one(^-1).

So

a Flushdraw have odds of 2:1 when you shove it all-in on the Flop.

You add the 'one' to the two so you get (2+1)=3

now you do 3 to the power of -1 (3² but then the -1) and you get 0.3333, thats the percentage if you do it times 100.

So 1.7:1 in my explanation, you have to add 1 by 1,7, do that to the power of -1 and you know your equity.

Hope this explains it

Otherwise try to study

This .pdf file that explains Math in Poker
Cheers