Drag formula but skip reference cells!

[mjleblanc]

I'm making a budget and i am trying to have a page with expenses for every month and then on a seperate page i want to have the total of each category of expenses (i.e. gas, loans, entertainment, etc.) in the expenses worksheet i have three columns for each month: 1st column: date of purchase, 2nd column: category, 3rd column: price.
I am using a sumif function on the totals worksheet to sum the prices of each category, so for instance the function for gas is (=sumif('monthlyexpenses!'B:B,"gas",C:C)
Now I want to be able to just drag across to auto fill the next columns in the expenses sheet so that august will have a function of (=sumif('monthlyexpenses!'E:E,"gas",F:F)
and i want to keep this increment for reference cells so that when i drag to september it will be H:H and I:I.
However everytime i drag across it just moves one reference column over.
In essence i want the formula to skip two reference columns each time i drag to the next column

 

[Gilliam]

I think this should do the trick
=SUMIF(OFFSET($B:$B,0,(COLUMNS($B$1:B1)-1)*2),"gas",OFFSET($C:$C,0,(COLUMNS($B$1:B1)-1)*2))

 

[mjleblanc]

thanks a ton! i was having so much trouble with this and i didnt want to use a pivot table because i dont like the layout