Consider the follow events

cash of $112 was used to purchase a used truck

cash of $80,000 was used to retire bonds

cash of $50,000 was received from the sale of an investment at a loss

cash dividends of $28,000 were received from an investment

plant assests were depreciated $12,000, under the straight-line method

compute the net cash flow from Investing activities

The answer is (62,000). Could you please explain how to solve this problem. I get confused between operating, investing and financing activities. If you could also explain the differences between them briefly I would appreciate it.