Discount method and interest rate method, interest rate method has a large range. According to the relevant information, the discount method refers to the deduction of interest in the current year of the loan and the repayment of the principal at maturity, and its effective annual interest rate = contract interest rate /( 1- contract interest rate). In the way of raising interest rate, the effective annual interest rate =2× contract interest rate, and the capital cost is twice the quoted interest rate.