Start with your percentage and divide by 100. A simple way to get the answer is to move the decimal two places to the left. 98 percent is equal to 0.98. When determining the percent of a number, you can use the decimal in your calculations, and you can even plug it into your calculator. 98 percent of 2000 = .98 x 2000. The answer is 1960, which you can check on your calculator.
Take the same percentage and express it as a fraction over 100. 98 percent is equal to 98/100. You can simplify this to the fraction 49/50. In some situations, a fraction is more useful than a decimal.
Convert your fractions to suit your needs. For example, you have 2500 individual units and 98 percent of the units can be sold. To determine the number of units that can be sold, you can cross multiply the fractions --- 98/100 and x/2500, in which x stands for the unknown number. 98/100 = x/2500. 98(2500) =x(100). x = 98(2500)/100 = 2450. 2450/2500 is the ratio of salable units to the total shipment. As expected, 2450/2500 reduces to 98/100, or .98