Matching principal and interest method: loan principal: 300,000 yuan, assuming annual interest rate: 6.000%, loan life: 30 years; Monthly repayment amount of principal and interest: 1798.65 yuan, total repayment amount of principal and interest: 647,565,438 yuan, * * interest payable: 347,565,438 yuan. The interest paid in 1 month is:1500; The first 1 month principal repayment is: 298.65; Since then, the monthly interest repayment amount has decreased and the principal has increased. (without considering the adjustment of interest rate in the middle)

Matching principal and interest method: loan principal: 500,000 yuan, assuming annual interest rate: 6.000%, loan life: 30 years; Monthly repayment of principal and interest: 2997.75 yuan, total repayment of principal and interest: 107965438 yuan, * * interest payable: 57965438 yuan. The interest paid in 1 month is: 2,500; The first 1 month principal repayment is: 497.75; Since then, the monthly interest repayment amount has decreased and the principal has increased. (without considering the adjustment of interest rate in the middle)