Google-sheets – ADD for more than two numbers in spreadsheet

Normally when I use functions in Google Sheets I can do something like this =K:K/J:J and get that column to update for its specific row for example.

http://imgur.com/a/Y7ofL

However with the SUM function this adds all of them. With a function like:

=SUM(D:D,C:C,E:E,G:G,F:F,H:H,I:I,J:J,K:K,L:L

and copy pasting it in a bunch of rows leads to every row having the same number instead of them depending on the numbers in their specific row. I tried changing to the ADD function however this only can add two at a time. As a temporary fix I have been using this function:

=SUM(O3,Q3,S3,U3,W3,Y3,AA3,AC3,AG3,)

and changing the number value for each row.

Is there a way to make a single formula that I can copy paste instead, something similar to the ADD function but with more than two values?