Computing Depreciation, Net Book Value, and Gain or Loss on Asset Sale end of its estimated $10-$year useful life. Zimmer disposes of the plane at the end of the seventh year.

a$.$ At the disposal date, what is the $(1)$ cumulative depreciation expense and $(2)$ net book value of the plane?

$(1)$ Cumulative depreciation expense $

$(2)$ Net book value $

b$.$ How much gain or loss is reported at disposal if the sales price is:

Note: Do not use a negative sign with your answers.

$\backslash$table$[[,$Sales Price,Gain or Loss$],[1.,$A cash amount equal to the plane's net book value,,$