formula in every 7th cell

[Smithgall]

I run across this type of need occasionally. In this lastest need i am filling in data across collumns. each column is a different day. What I would like to do is on every 7th collumn in (sunday) i want to total some of the data. for example if A1 is where the hours worked is listed i want to go to F2 and put the sum of teh past 7 days. since each collumn has a variety of stats that i add and delete according to what i am tracking (units sold, calls made, hrs worked, etc) I may need to add SUM cells occasionally as i decide different criteria to track.

QUESTION
How do i avoid going through 365 collumns and looking for each 7th column to add my formula. is there a way to do this automatically?

 

[Peter Compton]

You will struggle to do this if your dates are in columns because Excel only has 256 columns whereas it has 65536 rows (more in Excel 2007). So I would put all your days in rows descending one column. Then what you need to do is to put the first formula in the cell you need (e.g. if your data goes in the range A1:A365, you might want your first formula in cell B7, for instance). What you then do is to copy the six blank cells and the cell with the formula in (B1:B7 in this example) and paste that down to a row that is a multiple of 7 (such as B364 in this example). That way you have copied all the blanks and all the formulas into every 7th row in one fell swoop without having to go through the spreadsheet finding every 7th row. Hope this is clear!