本设计完成了要求的所有功能，.能存储足够大的大整数并进行相应的加减法运算。用户界面友好，有用户使用说明,每一步操作都有说明与提示。程序运行通过，有详细的解释说明。-the design completed all the required functions. Can store large enough large integer and the corresponding addition and subtraction operations. User friendly interface, users note, every step of the operation have notes and hints. Running through a detailed explanation.