Matching principal and interest method: loan principal: 200,000 yuan, assuming annual interest rate: 4.900%, loan life: 20 years; Monthly principal and interest payable: 1308.89 yuan, total principal and interest payable: 3 14 133.6 yuan, total interest payable: 65,438 yuan. The interest paid in 1 month is: 816.67; The first 1 month principal repayment is: 492.22; Since then, the monthly interest repayment amount has decreased and the principal has increased. (without considering the adjustment of interest rate in the middle)