What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Unfortunately you can't use configurable list widget to perform calculations. You will have to use some other form tool to make your calculations.
You can use conditions with combination of radio buttons and textfields with conditions.
Folllow these guides i provided to achieve your goal
Please let me know if i can be of more assistance to you.