Calculate the book value for each of the four long-term assets at December 31, 2015. Slouch Sandwich Shop had the following long-term asset balances as of December 31, Slouch purchased all the assets at the beginning of 2013(3 years ago) the building is depreciated over a 20-year service life using the double declining-balance method and estimating no residual value. the equipment is depreciated over a 10-year useful life using the straight-line method with an estimated residual value of $10,000 the patent is estimated to have a five-year service life with no residual value and is amortized using the straight-line method