On April 1, 2014, Mills Company acquired equipment for $125,000. The estimated useful life is six years, and the estimated residual value is $5,000. Mills estimates that the equipment can produce 25,000 units of product. During 2014 and 2015, respectively, 3,000 and 4,200 units were produced. Mills reports on a calendar year basis.

Required:
Calculate depreciation expense for 2014 and 2015 under each of the following methods (assume that Mills calculates depreciation to the nearest month in the year of acquisition):
1. Straight-line method.
2. Production method (units of output).
3. Double-declining balance method.
4. Sum-of-the-years’ digits method.