Something to add here ...

If you are a limit player, and you want to make the right decisions on your draws (and a limit player has to make correct decisions with small equity differences over and over to be a winning player), you absolutely must know the numbers on the chances to improve with a certain # of outs. This doesn't take any math skills other than being able to count and add and compare 2 numbers to each other. If you can count the # of bets in the pot, and count your effective outs, and look up a # on a table, you have all you need to make the percentage play on a draw. If you aren't doing this now, start now! Either use one of the estimation rules, or memorize an outs chart, or tape the chart to your computer. But one way or another, you need to know when you are paying too much for a draw and should fold. NL players may be losing players because they make a big mistake they shouldn't once in a while, but a limit player tends to lose money by making small mistakes over and over that may each only lose as little as a tenth of a small bet.