说明：  EDA可编程逻辑设计 设计一个简易十进制以内的计算器 可以利用按键和数码管作为计算器的输入和输出，能完成十以内的整数的加、减、乘、除（商和余数）运算，预算结果可以是正/负数，结果的绝对值可以超过十，且能够正确显示。
(EDA design of programmable logic to design a simple decimal calculator can be used within the tube as the calculator keys and digital inputs and outputs, to complete within ten integer add, subtract, multiply, divide (quotient and remainder) operations, budget results can be positive/negative, the absolute value of the results can be more than ten, and can display correctly.)