First of all, we should make clear what types of three numbers are, such as integer, real number and floating point number. The two numbers that need to be compared with each other are of the same type. If the types are different, you need to convert them to the same type. After the types are the same, compare them with each other and with 1 and 2 to get a large number. Compare a large number with another number, and compare the decimal after comparison with the decimal of the first comparison. You can get the size arrangement of three numbers after three times.