Zook Incorporated, had net income for 2013 of $4,000,000. Additional information is as follows: Amortization of patents $ 45,000 Depreciation on plant assets 1,650,000 Long-term debt: Bond premium amortization 65,000 Interest paid 900,000 Provision for doubtful accounts: Current receivables 80,000 Long-term nontrade receivables 30,000 What should be the net cash provided by operating activities in the statement of cash flows for the year ended December 31, 2013, based solely on the above information

I know how to solve the answer and everything given above. All I want to know is that what is the treatment of Interest in this case. Isn't Interest part of the Operating Section, or Interest is always part of the Financing Section. Can someone please explain what is the treatment of Interest Paid and Interest Received on the Cash Flow.