Set value to radio buttons and get the sum of the selected radio buttons

Hi, 

I need help in setting values to radio buttons and getting the sum of the selected radio buttons. 

Please note that I am a novice and am excited to learn more about this. 

I am creating this form for a client and each radio button should have its value. 
For example,

Choice1 == "0"; 
Choice2 == "1";
Choice3 == "2";
Choice4 == "3";

it's the same with the rest of the radio buttons. 

Each question is grouped so in SCORE1, there are 5 groups. 

this is what I've done so far, setting a value for each radio button.. not sure if this is the best option. 

I'm really lost with the total text field where it should get the sum of the selected radio buttons only. 
So say in: 
Group1, Choice1 is selected then value is at 0;
then add the choice on group2 which is at 1 and so forth. 
Let me know how to go from here. Thank you!