How to get Excel 2010 to automatically change the row numbers in a function

I am computing a final report and I need to compute the value of a specific column in a spreadsheet of 150 rows

The function which i wrote is

=((SUM(I6:W6)/75)*.35*4)+(Y6*.1)+(Z6*.15)+(AA6*.3)+((AB6*4)/10 *.1)

is working fine but then I am forced to copy it to each row of that specific column and update the row numbers to get the correct answer.

For example ,if I wanted to calculate the value for row number 16 for that column,I would have to manually enter this :

=((SUM(I16:W16)/75)*.35*4)+(Y16*.1)+(Z16*.15)+(AA16*.3)+((AB16*4)/10 *.1)

This process is going to take a lot of time if I do it for all the records,any inputs on how to automatically get excel to update the row numbers ?

Thanks !!

Just double-click the lower-right-little-black-square that will appear on the cell containing the formula

This is a standard feature of Excel.

You have just to copy "dragging".

I am looking for a video to post here.

Edit. Videos

http://www.metacafe.com/watch/1084306/excel_trick/

http://www.youtube.com/watch?v=VoQmaLh2L-A

HTH!