Years left of useful life sum. From the Detail Type dropdown select Depreciation. To calculate depreciation subtract the assets salvage value from its cost to determine the amount that can be depreciated.
To arrive at the book value simply subtract the depreciation to date from the cost.
The useful life is 20 years and the salvage value is 1000 so the depreciation for each year is 2450 50000 - 1000 divided by 20. In the Name field select journal for posting depreciation. In the Transaction type field select Depreciation transaction type. Set up a depreciation account.