Recording a Change in Estimate, an Error Correction, and a Change in Accounting Principle

On December $31,$ Year $4,$ Alexa Company is preparing adjusting entries for its annual year$-$end. The following issues confront the company.

estimated total useful life is $6$ years instead of $10.$

depreciation had been recorded on this equipment for Year $1$ or Year $2,$ but it was recorded for Year $3.$

$$80,800.$

a$.$ For equipment #$101,$ provide the required adjusting entry for depreciation expense at December $31,$ Year $4.$

Note: Round answers to the nearest whole dollar.

b$.$ For equipment #$502,$ provide the required adjusting entry for depreciation expense at December $31,$ Year $4.$

c$.$ For equipment #$502,$ provide any necessary correcting entry. Ignore income taxes.

d$.$ In reporting comparative income statements in Year $4,$ what net income amount is presented for Year $3?$