Formula for multiple sheets

[acleveland38]

Hello, I am trying to build a workbook that is 52 sheets (one per week of the year). One requirement is that there be a "last 4 weeks" cell on each sheet after week 4. I am curious if there is a formula that will add a assigned cell for the last 3 sheets, that would be pastable as to not have to do the formula for all 48 pages. For example, net sales will automatically add the last 3 weeks and current sheet to provide a 4 week total. I can build a formula for this calculation but more looking for if there is an option for a sheet basis.