Calculate a loan of 654.38+10,000 yuan, with an annual interest rate of 6.8%, and how much to pay back a year. Assuming that the total loan amount is P (principal) and the monthly repayment amount is set to M, it is a common calculation method to calculate the monthly repayment amount by equal principal and interest repayment method. The monthly payment formula of m is: m = p× [r/(1-(1+r) (-n)] where r is the monthly interest rate (annual interest rate/12) and n is the total number of months (number of years×12). According to the subject conditions, P= 100000, the annual interest rate is 6.8% (decimal 0.068), and the loan term is 1 year. Substitute it into the formula to calculate. The calculation result is: 8643.46 yuan. It's still 8643.46 yuan a year.