Operating cash flows $($such as new revenues earned from an investment$)$ are calculated after$-$tax by multiplying them by $(1-$tax rate$),$

but a different operating expense that is noncash in nature, depreciation expense, is transformed into its after$-$tax state by multiplying

it directly by the tax rate. Why are they treated differently? In other words, why isn't the depreciation expense also multiplied by $(1-$

tax rate$)?$ You may provide an example if it helps you to explain this difference.