Operating section

• Net Reven-numberue - Inflows or other enhancements of assets of an entity or settlements of its liabilities during a period from delivering or producing goods, rendering services, or other activities that constitute the entity's ongoing major or central operations. Usually presented as sales minus sales discounts, returns, and allowances.
  
• Expenses - Outflows or other using-up of assets or incurrence of liabilities during a period from delivering or producing goods, rendering services, or carrying out other activities that constitute the entity's ongoing major or central operations.

Non-operating section

• Other reven-numberues or gains - reven-numberues and gains from other than primary business activities (e.g. rent, patents). It also includes unusual gains and losses that are either unusual or infrequent, but not both (e.g. sale of securities or fixed assets).
  
• Other expenses or losses - expenses or losses not related to primary business operations.

Irregular items

They are reported separately because this way users can better predict future cash flows - irregular items most likely won't happen next year. These are reported net of taxes.

• Discontinued operations is the most common type of irregular items. Shifting business location, stopping production temporarily, or changes due to technological improvement do not qualify as discontinued operations.
  
• Extraordinary items are both unusual (abnormal) and infrequent, for example, unexpected nature disaster, expropriation, prohibitions under new regulations. Note: nature disaster might not qualify depending on location (e.g. frost damage in Canada would not qualify whereas in tropics would).
  
• Changes in accounting principle is, for example, changing method of computing depreciation from straight-line to sum-of-the-years'-digits. However, changes in estimates (e.g. estimated useful life of a fixed asset) do not qualify.