Formula copying

[durallymax]

Sorry couldnt think of a good descriptive title.

Heres what im getting at.

Im doing some inventories in excel for our farm.

Im using formulas such as =SUM(C8-D8) and =SUM(D12*S12) and so and and so forth.

However when it comes time to do the simple ones in order going down each row 1,2,3,4,5,6, and so on and so forth ive just been copying and pasting say =SUM(C8-D8) and then changing the number to the rows number in the formula box. This is extremely time consuming when there are hundreds of rows.

I was wondering if there was a way I could get Excel to always want to multiple Column A and Column B or similar? Im sure there is an easier way to do this.


Thank you.