What needs to be repaid is the principal and interest. Principal refers to the amount of money borrowed by the borrower from the lender, including principal and interest. Interest such as 360 IOUs is a repayment method of 360 IOUs, which is also called installment repayment. It is necessary to calculate and collect the equal amount of repayable principal and installment fee on schedule. The installment rate is differentiated by the system according to the comprehensive qualification of users, and the page displayed after approval shall prevail.