Sum and subtraction multiple cells

Hi guys,

I`m hoping someone can help with what may be a basic query!

I want to write a formula whereby I calculate the sum of multiple cells and subtract it from the total of multiple cells:

=SUM(C2:C6, G2:G6,K2:K6,B10:B13,G10:G13,K10:K13,O10:O13)-D2:D6,H2:H6,L2:L6,D10:D14,H10:H14,L10:L14,O10:O14

Where am I going wrong? Using google sheets! do i need two formulas?

Here is my sheet: See the top line tab

https://docs.google.com/spreadsheets...it?usp=sharing

Cell C17

Thanks

I haven't looked at the sheet but you're missing another SUM function:

=SUM(C2:C6, G2:G6,K2:K6,B10:B13,G10:G13,K10:K13,O10:O13)-SUM(D2:D6,H2:H6,L2:L6,D10:D14,H10:H14,L10:L14,O10:O14)

Thanks Rory. Simple as that!