Calculate Answers From Several Questions to Add Error Message or Warning

I have 5 questions asking the percentage of funding source for a project.

I already restrict the limit for the answer for 0-100.

I want to add a question that calculates the answer from those 5 questions, and when they add up it cannot exceed 100 (total percentage). And if they exceed 100, I want to add some error message. How can i do that? Thanks.

@wiydiy, maybe this post discussed previously should help you solve your issue: