autosum function

[danny_myrick_1965]

i am trying to use autosum to add the values in every 8th cell of a column.  the formula i tried was =sum(f11:f419*(mod(row(f11:f419),8)=0)). this is an excel formula i found online, but it is not working as it should. i am a new excel user

[#2]

@danny_myrick_1965 

You have to enter the formula with ctrl+shift+enter if you don't work with Office 365 or Excel for the web or Excel 2021.

The screenshot is from Excel 2013 and it works as intended after the formula is confirmed as an arrayformula with ctrl+shift+enter.