1. First, we must determine the interest rate and repayment method of the mortgage. There are generally two repayment methods of mortgage: average capital and equal principal and interest.

2. Secondly, the repayment method of equal principal and interest is adopted. According to the loan principal of 80,000 yuan, the repayment period is 7 years, and the monthly repayment is about 1, 2 1 yuan. According to this repayment plan, the total repayment interest paid off after 7 years is 35,000 yuan, and the total repayment amount is115,000 yuan.

3. Finally, according to the repayment method of equal principal, the repayment period is 7 years, the loan principal is 80,000 yuan, and the annual repayment period is 12 months. The monthly repayment amount is 944 yuan, the total repayment amount is 102000 yuan, and the total repayment interest is 22000 yuan.