How to calculate the good or ill luck of the license plate

For example, if the license plate number is Guangdong A35689, then the calculation method of the license plate number query is to take the last four digits 5689 and divide it by 80 to get a number 5689/80 = 71.1125 and then remove the integer part. Keep the decimal part of 71.1125-71(integer part) = 0.1/25, and then multiply this number by 80, and the result is 0.1. (If the license plate number contains letters, the letters should be removed and only the numbers should be taken. E.g., 4W568, only 4568, W256, 256, 5A69, 56A8, only 568).