On January 2, year 3, Gray purchased a manufacturing machine for $864,000. The machine has an eight year estimated life and a $144,000 estimated salvage value. Gray expects to manufacture 1,800,000 units over the life of the machine. During year 4, Gray manufactured 300,000 units.

Calculate depreciation expense on the manufacturing machine for year 4 for each method listed.

1. Straight line
2. Double declining balance
3. Sum of the years' digit
4. Units of production