单片机课的实验作业。功能是实现一个有着简易计算功能的计算机，利用LCD屏互动。可以做加减乘除运算。特别的，给出了四个内置公式：等差数列求和，一元二次方程求根，排列，组合。-Our project is aiming at making a calculator to help the users calculate particular formulae. As long as the user correctly input the values of parameters needed in