The purpose of this applet is to compute an athlete's On Base Percentage, that is, the percentage of times that they get on base in a baseball or softball game. This number does not include walks or sacrifice plays.
The first input component is the number of times the player gets on base. The second is the number of times that player got up to bat. The output component is the quotient, or the number you get when you divide the first input component by the second, or the on base percentage. When the user pushes the "compute" button, which in this case is labeled "Compute On Base Percentage" the first number is divided by the second number to produce a new number. This new number will always be a decimal as it is a percentage, unless the player got on base every single time they were up to bat, in which case their on base percentage would be 100 percent and would yield the number 1.