Multiplying Values of Drop Down and Radio List to Show in Text Box?

Hi, I have a Point Table like below that has Drop Down list and 2 Radio Button lists. After selecting values I would like to show the multipled values and the total of the sections in each Text Box. I want to do it on server-side.
For example
DDL1*RB1*RB2 = (THE VALUE1) DDL2*RB3*RB4 = (THE VALUE2)
Total: (THE VALUE1) + (THE VALUE2)

Example.aspx
<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server"> <br /> <h3 style="text-align: center">Point Table</h3> <br /> <table style="width:100%;"> <tr> <td style="width:73px;">Section</td> <td s ...