Matching principal and interest method: loan principal: 2,900,000, assuming annual interest rate: 4.900%, loan life: 20 years, monthly repayment amount of principal and interest: 65,438+08,978.88 yuan, total repayment amount of principal and interest: 45,549,365,438+0.2 yuan, and total interest payable: 60. The interest paid in 1 month is:11841.67; The first 1 month repayment principal is: 7137.2438+0; Since then, the monthly interest repayment amount has decreased and the principal has increased. (without considering the adjustment of interest rate in the middle)