Total asset cost plus depreciation expense equals book value.

Total Asset Cost

The sum of all costs incurred to acquire an asset and make it ready for its intended use.

Depreciation Expense

Depreciation expense is the allocation of the cost of a tangible asset over its service life, reflecting the decrease in its value over time.

Book Value

The net value of a company's assets minus its liabilities, often used as an estimate of an asset's value if it were to be liquidated.