1939902.py

#!/usr/bin/env python

# http://stackoverflow.com/questions/1939902

from __future__ import division
import itertools

operands = [1, 2, 3, 5, 7]
operators = ['+', '-', '*', '/']

def blend(operands, operators):
    r = []
    for i in range(len(operators)):
        r.append(operands[i])
        r.append(operators[i])
    r.append(operands[-1])
    return r

for j in itertools.product(operators, repeat=len(operands) - 1):
    for i in itertools.permutations(operands):
        expression = ' '.join(map(str, blend(i, j)))
        print expression, '=', eval(expression)