$1.$ Fill in depreciation expense in year $3$ under each depreciation method when residual value is $$30,000$ and useful life is $3$ years:

Depreciation method:

Straight$-$line fill in the blank $1$

Units$-$of$-$Output fill in the blank $2$

Double$-$declining fill in the blank $3$

$2.$ Fill in the book value at the end of year $1$ under each depreciation method when residual value is $$36,000$ and useful life is $4$ years:

Depreciation method:

Straight$-$line fill in the blank $4$

Units$-$of$-$Output fill in the blank $5$

Double$-$declining fill in the blank $6$

$3.$ Move the Useful Life slider from $3$ years to $4$ years and complete the sentence.

Depreciation expense each year under every method is

when the cost is spread over a longer useful life.