The translation may be awkward. Please tell me the detailed explanation and answer.

1. Double-declining-balance method On January 1, 2018, Company A purchased one mechanical device. The acquisition cost of machinery is 800,000, and the content training is 8 years. The double-declining-balance method is applied separately when the residual value of the machine is 300,000 and 100,000, and the depreciation cost of the machine in 2020, 2021 and 2022 is calculated and depreciated. If there is a difference, please explain why. (Round to the nearest whole number when calculating depreciation.)

2, sum-of-the-years'-digits method On October 1, Company A paid 1,600,000,000 cash and purchased the building. It is estimated that this building can be used for 5 years. The estimated residual value of the building is 100,000,000. If you use the sum-of-the-years'-digits method, calculate the depreciation of the building on your statement of comprehensive income.