Sum of row n through last row

Question

I want to create a TOTAL row at the top of my spreadsheet. In this row, each cell should be the SUM of the values in the column below the TOTAL row.

So for example, i

Answer 1

=(B3+C3+D3+E3+F3+G3+H3+I3+J3+K3+L3+M3)

This worked for me. 3 being the row number When you Drag the box downward the formula transfers down and changes the row number automatically for each row.

After I put another heading several rows down adding the word SUM into the formula worked.

=SUM(B19+C19+D19+E19+F19+G19+H19+I19+J19+K19+L19+M19)

Not sure if it was necessary. But just copy pasting the first formula I used into the lower segment made an error message.