Need a formula

[Goins Needs Help]

I need a formula that will allow me to seperate monthly expenditures from a
monthly report with YTD totals only. I would like to input July's
expenditures in column B, and type a formula in colums C - AA that substracts
the past month's expenditures and thus leaving each colum with that month's
total expenditures only. I'm was thinking of using a few columns as
"dummies" far out in the worksheet. Again, I'm looking for suggestions and
ideas. Also, I've seen the "index" formula used to do something similar but
I don't remember the set up.

Help

 

[Pranav Vaidya]

I would use colums on far left as dummy and do the YTD.