The daily interest rate is five ten thousandths. This is simple interest. The daily interest rate for an overdraft of 2000 yuan is 1 yuan. Monthly compound interest is the sum of unpaid principal plus interest this month to calculate interest. For example, if you overdraw 2000 yuan this month, the daily interest rate is five ten thousandths, which is one yuan a day. By the end of the month, the interest will be paid to 30 yuan, and the interest will be calculated according to the principal of 2030 yuan next month, that is, compound interest every month. That is, the interest of next month is calculated according to the sum of the outstanding principal of last month plus the interest that has already been generated. This is compound interest, and the interest in usury is compound interest.