=AVERAGE(OFFSET(A$1,10*(ROW()-ROW(B$1)),0,10,1)) in B1, and copy down.
--
David Biddulph

"guitara" wrote in message
ups.com...
I have a column of numbers in A, and I want B1=average(A1:A10) ,
B2=average(A11:A20), B3=average(A21:30)..........................

Is there any way to do this calculation? I can not input each equation
in column B, since I have lots of data.

Can I set a function by myself?