some would say a running total, I would say shared variables...they do the same thing. For some reason, running totals confuse me, DBlank uses them all the time.
shared variables would be something like:
page header formula:
shared numbervar tot:=0;
"" //hides the output
detail formula:
shared numbervar tot;
tot := tot + {table.field};
"" //again to hide the running total output.
page footer formula:
shared numbervar tot;
tot;
HTH