數學問題：2 2 2 = 6……

 2    2    2  =  6
 3    3    3  =  6
 4    4    4  =  6
 5    5    5  =  6
 6    6    6  =  6
 7    7    7  =  6

請給上列各個等式加上合適的算術或數學符號，只能加符號不能加數字。

Python

#!/usr/bin/env python
#encoding:utf-8
'''Risk2S'''
import math
list = ['+','-','*','/']
print "sign:",list
for i in xrange(2,10):
    for y in list:
        for x in list:
            b = ("(%d)%s(%d)%s(%d)"%(i,x,i,y,i))
            if eval(b)==6:
                print (b+'='+'6').replace('(','').replace(')','')

多重循環。