Hello

1) Depreciation= Asset cost devided by equal period of expected product life

Ie:Depreciation=1000/10=100, then one hundred to be deduct each month from the total cost .

2) cost of production means all Direct cost+indirect cost needed to produce the goods.

Ie: Cost of raw material+Labour cost+fixed+ Admin cost+cost+Rent+Rate+Tax=Cost of production.
COP+selling/distribution cost=cost of sales
Sales-Cost of sales=Profit