Running Total in Report

[lryder]

I need to keep a running total on multiple fields, and these fields are each have a different value. Some are null to reflect a N/A value and some are Y/N and reflect different values also. ie question 1 is Y/N/Null and if Y vaule is 15, question 2 is Y/N/Null and if Y value is 10, question 3 is 0/5/10/Null.