Compiling a checkbox form to a spreadsheet

Hey so I have a client that wanted me to create a form that has four options for each question for example
1.) Morning is when I feel best
A little of the time
Some of the time
Good part of the time
Most of the time
Each answer is supposed to have a number correlated with it i.e:
A little of the time = 1
Some of the time = 2
Good part of the time = 3
Most of the time = 4
These numbers are supposed to be added up and calculated to have a total number. How do I make it so that each response checked is added up when the response is marked? I know the form needs to be connected to a spreadsheet, which it is, but every time I fill out the form, the responses added to the spreadsheet are the same responses that I placed in the form. I want to correspond these answers to numbers that can be added up in a spreadsheet.
Any help on this subject would be awesome!!!