Formula Help
 

I need a formula to help me with mid month and end of month totals of
products. Is there a formula that I can put in the Mid Month colum to get it
to add up from the start of the month to the middle of the month. I have a
reports worksheet with the following information.

Column A Column B Mid month Total End
month Total

material type material weight would be a total of would
be column b -
column B from 1st
Mid Month total
of month to approx
midlle of month

Information in column b is from a seperate worksheet via a VLOOKUP formula.
Any help would be greatly appreciated.