Classify each of the following transactions as an operating, investing, or financing activity, even those that would not appear explicitly on the statement of cash flows. Some transactions may be classified in more than one category:
1. Purchase of machinery for cash.
2. Issuance of common stock for cash.
3. Sale of inventory on account.

4. Purchase of outstanding stock (treasury stock) for cash.
5. Sale of land held as a long-term investment.
6. Purchase of a building for cash and a mortgage payable.
7. Cash payment for principal and interest on an outstanding debt.
8. Cash payment on accounts payable.
9. Payment of a cash dividend.
10. Payment of wages to employees.