Extend jQuery functionality

I am trying to update HTML input value with a calculation I am doing through jQuery. The calculation is based on the selections the user made in a system. Imagine it like 3 steps, in each one you make a selection: Step 1 -> show box 1 with a number of options. Select an option, Click 'Next'... Step 2 -> show box 2 with a number of options. Select an option. Once you click on the option, the name of that option automatically gets updated with the jQuery calculation. Click 'Next'... Step 3 -> show another box with more options. Option is updated as well. Based on the selections in each box, a calculation will be performed through jQuery. Eg. In box 2, when you select something, I want to update the name automatically based on some calculation (we will need the selection made in box 1, a constant input number, and the selection in box 2) . Box 2 has six contests (li elements). Each of this contest info has its own ID and the actual value is just a number as you can see in the HTML code below. And I use those values for the calculation. What I actually want to do is to update an HTML input value with something through jQuery based on multiple selections in each step. I need to retrieve EACH selection in jQuery, get its value or some input data, use them for the calculation and then update the option name. I will tell you more information and show you source code etc when I pick the person who can help me out with it.