formula to subtract pairs of cells

I have a spreadsheet which I want to: E2=C3-C2, then E3=C5-C4, E4=C7-C6 etc for lots of cells:

So I am looking for a formula which I can drag down which minuses values in pairs rather than consecutively.

I tried SUM(OFFSET) but only added values, not minus.

Any help greatly appreciated!

CodePudding user response：

If you must use a formula in E2, then try:

=INDEX(C:C,ROW()*2-1)-INDEX(C:C,ROW()*2-2)

CodePudding user response：

Your idea of using OFFSET can be made to work. In E2 put

=OFFSET($C$1,2*ROW()-2,0)-OFFSET($C$1,2*ROW()-3,0)

and copy down.