First of all, in order to let users enter their data in your table on Frontend, you need to use Editable Fields option. Open your table editor https://prnt.sc/fel2kk, select needed fields. Then click on the “Add editable field” option (1) and then click on “plus” icon (2) https://prnt.sc/fel3b7. Now users can enter their data in your chosen fields on frontend. You can find additional information here https://supsystic.com/documentation/editable-fields/.
Here is the example of simple formula (1) https://prnt.sc/fel73k. All formulas you should write in the F(x) field, starting from symbol =.
These two articles will help you to create your desired calculator https://supsystic.com/documentation/use-formulas-tables/