Which of the three categories would these items fall into: operating (O), investing (I), or financing (F)

Sale of common stock (F)
Sale of land (I)
Purchase of treasury stock (F)
Merchandise sales (O)
Issuance of a long-term note payable (F)
Purchase of merchandise (O)
Repayment of note payable (O)
Employee salaries (O)
Sale of equipment at a gain (O)
Issuance of bonds (F)
Acquisition of bonds of another corporation (I)
Payment of semiannual interest on bonds payable (O)
Payment of a cash dividend (F)
Purchase of a building (O)
Collection of nontrade note receivable (principle amount) (I)
Loan to another firm (I)
Retirement of common stock (F)
Income taxes (O)
Issuance of a short-term note payable (F)
Sale of a copyright (I)

I have indicated my answers in parenthesis. Any help would be appreciated.

Thank you

morgaine300

Correct if it's short-term. Usually if it doesn't indicate otherwise, we assume it is. (But you never know what some textbook is going to do.)

That's a bit of a trick question. The gain goes into the operating section when doing the indirect method. But the sale itself (gain or not) is an investing activity. (The reasons a gain would be adjusted in the operating section for indirect is because it doesn't belong there and needs to be removed from the net income figure.)

See note on the other note payable.