Try this:

=IF(B$1="","",IF(ROWS($1:1)<=CEILING(COUNT(A$1:A$1 2)/B$1,1),SUM(OFFSET(A$1,(ROWS($1:1)-1)*B$1,,B$1)),""))

result will be in other column with parameter
interval i.e., value of (B1) i.e., 3 or 6 or 9 or 1 etc.

If you use an interval of 1 then you have to copy the formula down to a
number of cells that's equal to the size of your range.

Biff

"Mujeeb ur Rehman, FBL-GRW-PK"
m wrote in message
...
There are 12 figures in a column (A1:A12). B1 is a parameter Cell. when I
enter 3 in the parameter cell (B1), result must be {sum(A1:A3),
sum(A4:A6),
sum (A
7:A9), sum(a10:a11)}. I Mean to say sum function must be handled with the
paramenter cell (B1), and result will be in other column with parameter
interval i.e., value of (B1) i.e., 3 or 6 or 9 or 1 etc.