Adding two sets of global variable in ssrs

I am trying to add from two separate text boxes from different datasets I had to create a code to summarize (codes below) giving a total. What I am trying to do is get GapTotal + GapTotal2 together into a separate dataset. Unfortunately I get a blank. Can anyone help? Thank you in advancePublic GapTotal AS Integer = 0Public Function Sum(ByVal Value As Integer) As IntegerGapTotal = GapTotal + ValueReturn ValueEnd FunctionPublic GapTotal2 AS Integer = 0Public Function SumIt(ByVal Value As Integer) As IntegerGapTotal2 = GapTotal2 + ValueReturn ValueEnd Function