# 最大公约数，最小公倍数 def yueshu(num, alist=None):
    """  这个方法是核心  :param num: int  :param alist: None  :return: alist  """  if alist == None:
        alist = []
    for i in range(2, num // 2 + 1):
        if not num % i:  # 整除  alist.append(i)
            return yueshu(num // i, alist)
    else:
        alist.append(num)
    return alist


def big_small(num1, num2):
    list1 = yueshu(num1)
    list2 = yueshu(num2)
    alist = []
    for i in list1:
        if i in list2:
            alist.append(i)
            list2.remove(i)
    pub = 1
    for i in alist:
        pub = pub * i
    pub2 = num1 * num2 / pub
    return pub, pub2


if __name__ == '__main__':
    big, small = big_small(15, 18)
    print big, small

自己写的，不一定对，哈哈哈哈