The formulas to calculate depreciation cost are:

1. Annual Depreciation (\(d\)):

\[ d = \frac{Co - Cn}{n} \]

2. Accrued Total Depreciation (\(Dm\)):

\[ Dm = m \cdot d \]

3. Book Value at the End of \(m\) Years (\(Cm\)):

\[ Cm = Co - Dm \]

Where:

• \(d\) is the annual depreciation.
• \(Co\) is the original cost.
• \(n\) is the useful life in years.
• \(Cn\) is the salvage value or the scrap value.
• \(Dm\) is the accrued total depreciation up to \(m\) years.
• \(m\) is the age of the property at any time less than \(n\).
• \(Cm\) is the book value at the end of \(m\) years.