Answer and Explanation:
As per the data given in the question,
The preparation of the operating activities section of the cash flow statement using the indirect method is shown below:
Cash flow from operating activities:
Net income $21,000
Add: Depreciation $4,000
Less: Accounts receivable expense -$9,000
Add: Inventory decrease $4,000
Add: Salaries payable increase $900
Net cash flow provided by operating activities $20,900
Net income is added because it provided before adjustment.
Depreciation is added because it is non cash expense.
Accounts receivable expense is deducted because it is trap in account receivable.
Inventory decrease is added because it depicts that the inventory is converted in cash.
Salaries payable increase is added because it shows cash is not paid which rise the level of cash.