I have a table for sales in each month of the year (have used only 6 mths is
example) and want to be able to calculate the total sales for any given
period. The given period.The "from" and "to" will be sourced from two other
cells, I have put these cells in " " in my example.
eg
Period from "A"
Period to "N"
Table as below
Period J A S O N D
Sales 1 2 4 1 3 6 Answer = 10 (2+4+1+3)
Sales 2 3 4 1 4 3 Answer = 12 (3+4+1+4)

I have thied the IF fuction but gets complicated with the limitation of 7
variables as my real table is 12 months.