please answer asap

On January 1, 20X1, Mills Company acquired equipment for $120,000. The estimated useful life is six years, and the estimated residual value is $4,000. Mills estimates that the equipment can produce 20,000 units of product. During 201, respectively, 5,000 units were produced. Mills reports on a calendar-year basis. Required: Calculate depreciation expense for 201 under each of the following methods: 1. Straight-line method 2. Units of production 3. Double-declining balance method 4. Sum-of-the-years' digits method