1、具备基本的加减乘除功能；支持由括号和运算符组成的表达式的运算。

2、使用android界面元素设计用户友好的界面。

3、能够存储多个计算结果，并提取出来作为下一个计算的操作数。

4、能够处理计算过程中的异常情况。

-1, with basic addition and subtraction, multiplication and division　computing support by parentheses and operator expression. 2, using the the android interface elements of design and user-friendly interface. 3, capable of storing a plurality of calculated results, and extracted as the next calculation of the operand. 4, it is possible to deal with the unusual circumstances of the calculation process.