Please explain the calculations as I am very confused with how to solve this question.

Yoshi Company completed the following transactions and events involving its delivery trucks. 2017 Jan. 1 Paid $20,515 cash plus $1,485 in sales tax for a new delivery truck estimated to have a five-year life and a $2,000 salvage value. Delivery truck costs are recorded in the Trucks account. Dec. 31 Recorded annual straight-line depreciation on the truck. 2018 Dec. 31 Due to new information obtained earlier in the year, the truck's estimated useful life was changed from five to four years, and the estimated salvage value was increased to $2,400. Recorded annual straight-line depreciation on the truck. 2019 Dec. 31 Recorded annual straight-line depreciation on the truck. Dec. 31 Sold the truck for $5,300 cash. Required: 1-a. Calculate depreciation for year 2018. 1-b. Calculate book value and gain (loss) for sale of Truck on December, 2019. 1-c. Prepare journal entries to record these transactions and events. Req 1A Reg 1B Req 1C Calculate depreciation for year 2018. Total cost Less accumulated depreciation (from 2017) Book value Less revised salvage value Remaining cost to be depreciated Years of life remaining Total depreciation for 2018 Calculate book value and gain (loss) for sale of Truck on Decem Depreciation expense (for 2017) Depreciation expense (for 2018) Depreciation expense (for 2019) Accumulated depreciation 12/31/2019 Book value of truck at 12/31/2019 Total cost Accumulated depreciation Book value 12/31/2019