Pages ’09: How to write Nested SUM?

Question

I'm setting up a basic time registration form for declarable hours spent on a project. The layout is easy: date — time from — time until — description. I want a cell-value to contain the sum of hours worked on a project (time until - time from).

I would say the correct formula would be =SOM(SOM(D9-C9):SOM(D40-C40)) (I'm using the Dutch version). But this isn't working. My registration starts from row 9.

Answer 1

Figured it out.. : must be ;. My mistake..