I borrowed 60,000% interest, the first year's monthly interest 150 yuan, and 3% is the annual interest divided by 12 months, that is, the monthly interest multiplied by the principal, which is the approximate interest of one month, because there are big and small months, or the daily interest divided by 30 days and multiplied by the principal is the real interest of one month, which is more accurate, but I just don't know what you are doing.