*get an annual net profit:   the amount of net profit in USD., after discounting all costs and expenditures .
*know the invest return (%):  get the value return related to your total invest in a year (feasible rate).
*know the profit efficient factor:   average sum of multiple rates that control the productivity and profitability 
*know the total operation cost:   all factors of costs and expenditures directly or indirectly.