=SUM(OFFSET(A1,5*ROW(A1)-1,0,5,1))

Put that in the first cell where you want the sums to start and copy it down
the column.

"sandy" wrote:

I have a column with 10,000 rows of numbers. I need to sum a1:a5, a6:a10,
a11:a15, and so on in groups of five, for all 10,000 rows. How can I do
this? Thanks much.