Let me try explaining this

The ROW function returns the row number of a single cell reference
ROW(reference)

The MOD function returns the remainder after number is divided by divisor
MOD(number, divisor)

Nested the ROW function in the MOD function which is to supply the number
argument, divided by 2 which is to sum every second cell will produced the
result
of 0

For example, to sum every second cell in the range A1:A20, the formula
could be this

=SUM(IF(MOD(ROW($A$1:$A$20),2=0,$A$1:$A$20,0))

Take note that this is an array formula which you must press Ctrl+Shift+Enter
at the same time to produce the desire result. Excel will add the curly
brackets to the formula

A better option is to use the DSUM function
--
Hope this help

Please click the Yes button below if this post have helped answer your needs

Thank You

cheers, francis





"SnackFoodGirl" wrote:

I am trying to figure out the formula for adding the nth cell in a given
column. I am using the formula below to add every 4th cell but it is just one
that I found on line. Can someone explain to me the components of this
formula so I can adapt it?

=SUM((C2:C213) * (MOD( ROW( C2:C213)+1, 4)=0))