Variables help needed

Hiya, 

I'm trying to create a knowledge check section in a compliance module, where the user has to beat the computer (basically when they get it wrong the computer gets the point instead). 

I've tried using variables and I can get the first question slides to update but then it all goes odd, I need the scores to add up as the user progresses through the three questions.

I'm part way there, but I can't seem to figure out where it's falling down, if anyone can help me that would be amazing!! :-)