能实现简单的加减乘除运算，这是我用了很短时间赶出来的，所以功能不是很完善。望原谅-Simple addition and subtraction to multiplication and division, this is a very short time I drive out, so the feature is not perfect. Wang forgive

简单的计算机功能,实现加减乘除.随便上传一点开通权限(Simple computer function realization. Just upload a add, subtract, multiply and divide open permissions)