报错 'float' object cannot be interpreted as an integer

  
def reduceNum(n):
    print ('{} = '.format(n),end="")
    if not isinstance(n, int) or n <= 0 :
        print ('请输入一个正确的数字 !')
        exit(0)
    elif n in [1] :
        print ('{}'.format(n))
    while n not in [1] : # 循环保证递归
        for index in range(2, n + 1) :
            if n % index == 0:
                n /= index # n 等于 n/index
                if n == 1: 
                    print (index) 
                else : # index 一定是素数
                    print ('{} * '.format(index),end="")
                break
reduceNum(90)

这是用python3 写的　报处这样的错误是为什么呢？

Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:24:40) [MSC v.1500 64 bit ( 
AMD64)] on win32 
Type “help”, “copyright”, “credits” or “license” for more information. 
>>> 0/200 + 1 
1 
>>> 1/200 + 1 
1

Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 17:54:52) [MSC v.1900 32 bit (Intel)]
on win32
Type “help”, “copyright”, “credits” or “license” for more information.

0/200 + 1
1.0

1/200 + 1
1.005
即在python3的环境下　１/200　他的数据类型是float 而不是int 当然会报错了
怎么修改中这个程序呢？
看下面的例子

1/200+1
#输出结果为　１.005
1//200+1
#输出结果为　１

所以我们就将程序改为

def reduceNum(n):
    print ('{} = '.format(n),end="")
    if not isinstance(n, int) or n <= 0 :
        print ('请输入一个正确的数字 !')
        exit(0)
    elif n in [1] :
        print ('{}'.format(n))
    while n not in [1] : # 循环保证递归
        for index in range(2, n + 1) :
            if n % index == 0:
                n //= index # n 等于 n/index
                if n == 1: 
                    print (index) 
                else : # index 一定是素数
                    print ('{} * '.format(index),end="")
                break
reduceNum(90)

就完美解决了