Hi All,

I have spreadsheet, in which col A has supplier name, Col B has year,
Col C has Months and Col D has number of units supplied by the
supplier.

Now to calculate the number of units received for Month of Mar-06, i
have to add the qty received in Jan-06, feb-06 and Mar-06. In the same
way, to calculate the qty received in Apr-06, i have to sum the qty
received in Feb-06, Mar-06 and Apr-06.

I am unable to find a way to do this. Please help.

Thanks for the help,
Navin