写一个四则运算器，要求从键盘读取数字

[root@localhost ~]# cat 1.py 
#!/usr/bin/python 
num1 = input("Please input first number: ")
num2 = input("Please input second number: ")
print "%s + %s = %s" % (num1, num2, num1+num2)
print "%s - %s = %s" % (num1, num2, num1-num2)
print "%s * %s = %s" % (num1, num2, num1*num2)
print "%s / %s = %s" % (num1, num2, num1/num2)

[root@localhost ~]# python 1.py 
Please input first number: 4
Please input second number: 3
4 + 3 = 7
4 - 3 = 1
4 * 3 = 12
4 / 3 = 1