On January 1, 2019, Button Manufacturing Company purchased a machine for $\$ 39,980$, and expects to use the machine a total of 32,000 hours over the next four years. Button set the residual value on the machine at $\$ 3,500$. Button used the machine 6,000 hours in 2019 and 7,200 hours in 2020.

Referring to Table 10-5, what is the amortization expense for 2019 if Button uses double-declining-balance amortization?
$\$ 9,995$
$\$ 19,990$
$\$ 18,240$
$\$ 9,120$

Step 1 ：The double-declining-balance method of depreciation, also known as the 200% declining balance method of depreciation, is a form of accelerated depreciation. This means that the depreciation expense is higher in the early years of an asset's life and lower in the later years.

Step 2 ：In this case, the cost of the machine is \$39,980 and the residual value is \$3,500. The useful life of the machine is 4 years.

Step 3 ：The formula for double-declining-balance depreciation is: \[\text{Depreciation Expense} = 2 \times \text{Straight-line rate} \times \text{Book value at beginning of year}\]

Step 4 ：The straight-line rate is calculated as 1 divided by the useful life of the asset. In this case, it would be 1/4 = 0.25 or 25%.

Step 5 ：The book value at the beginning of the year is the cost of the asset minus any accumulated depreciation. In this case, since it's the first year, the book value at the beginning of the year is the cost of the asset, which is \$39,980.

Step 6 ：Let's calculate the depreciation expense for 2019. Using the formula, we get: \[\text{Depreciation Expense} = 2 \times 0.25 \times 39980 = 19990.0\]

Step 7 ：The calculated depreciation expense for 2019 is \$19,990. This matches one of the options given in the question.

Step 8 ：Final Answer: The amortization expense for 2019 if Button uses double-declining-balance amortization is \(\boxed{\$ 19,990}\).