求最大公约数——辗转相除法（欧几里得法）
    a,b，大数放a，小数放b，a÷b=temp，若temp=0，则b为最大公约数；反之，b放到a中，temp放到b中，重复。

    尝试一：
    # 计算两个数的最大公约数，用函数做
    # greatest common division
    def getgcd(num1, num2):
    “””获取num1、num2的最大公约数”””
    _if num1 == num2:
    print(“The greatest common division is: “ + str(num1))
    elif num1 > num2:
    a = num1
    b = num2
    temp = a / b
    while temp:
    a = b
    b = temp
    temp = a / b
    print(“The greatest common division is: “ + str(b))
    elif num1 < num2:
    a = num2
    b = num1
    temp = a / b
    while temp:
    a = b
    b = temp
    temp = a / b
    print(“The greatest common division is: “ + str(b))

    num1 = int(input(“Please enter the first number:”))
    num2 = int(input(“Please enter the second number:”))
    get_gcd(num1, num2)

    结果：
    Please enter the first number:9
    Please enter the second number:6
    The greatest common division is: 7.416347076017091e+300

    思考：
    temp = a / b是商，要考虑余数。

    尝试二：
    # 计算两个数的最大公约数，用函数做
    # greatest common division
    def getgcd(num1, num2):
    “””获取num1、num2的最大公约数”””
    _if num1 == num2:
    print(“The greatest common division is: “ + str(num1))
    elif num1 > num2:
    a = num1
    b = num2
    temp = a % b
    while temp:
    a = b
    b = temp
    temp = a % b
    print(“The greatest common division is: “ + str(b))
    elif num1 < num2:
    a = num2
    b = num1
    temp = a % b
    while temp:
    a = b
    b = temp
    temp = a % b
    print(“The greatest common division is: “ + str(b))

    number1 = int(input(“Please enter the first number:”))
    number2 = int(input(“Please enter the second number:”))
    get_gcd(number1, number2)

    结果：
    Please enter the first number:25
    Please enter the second number:50
    The greatest common division is: 25

    Please enter the first number:9
    Please enter the second number:6
    The greatest common division is: 3

    最小公倍数
    两个数的乘积等于这两个数的最大公约数与最小公倍数的积
    # 计算两个数的最大公约数，用函数做
    # greatest common division
    def getgcd(num1, num2):
    “””获取num1、num2的最大公约数”””
    _if num1 == num2:
    b = num1
    # print(“The greatest common division is: “ + str(b))
    elif num1 > num2:
    a = num1
    b = num2
    temp = a % b
    while temp:
    a = b
    b = temp
    temp = a % b
    # print(“The greatest common division is: “ + str(b))
    elif num1 < num2:
    a = num2
    b = num1
    temp = a % b
    while temp:
    a = b
    b = temp
    temp = a % b
    # print(“The greatest common division is: “ + str(b))

    1. return b

    number1 = int(input(“Please enter the first number:”))
    number2 = int(input(“Please enter the second number:”))
    gcd = get_gcd(number1, number2)
    lcm = number1 * number2 / gcd
    print(“The lowest common multiple is “ + str(lcm))

    Please enter the first number:3
    Please enter the second number:9
    The lowest common multiple is 9.0