Form Calculations widget with Matrix fields - Is it possible?

I would like to create conditional calculations on the order form below but can't figure out how to make it work - any suggestions?

My goal is to calculate the total based on the items selected by the client on the form.  When I try to use the calculations widget, I don't see how to make this happen and I don't see the option in the conditions options. I went ahead and added text boxes listing the price of each item but I'm not sure this was the correct approach.

http://form.jotform.us/form/50845973726164

Thanks!

As instructed in this guide: http://www.jotform.com/help/259-How-to-perform-calculation-in-the-form, the calculation widget can be used only in the following fields:

1. Radio Button

2. Checkbox

3. TextBox

4. Dropdown

5. Text Area

It would not work in the matrix fields you have added. My suggestion would be to use a payment integration such as  Purchase Order. Please review this guides to help you accomplish what you need:

1) http://www.jotform.com/help/225-How-to-add-options-to-Payment-Forms

2) http://www.jotform.com/help/264-Create-Sub-Products-Based-on-a-Product-Option

3) http://www.jotform.com/help/296-How-to-Add-Tax-to-Your-Payment-Form

Let us know if you need anything else, we will be glad to assist you.