说明：  8051单片机乘法抢答器： 开机后，按0#键，随机出题，看到题目后从键盘输入答案 答题正确，蜂鸣器响3声 * 继续出下一题,如果不知道答案则按0c键， 提示正确的答案
(8051 multiplication Responder : Boot, press 0# key, random topic. see the topic from the keyboard input after answering correctly answer, buzzer ring for three acoustic* continue into the next issue. If we do not know the answer according to Key c 0, indicating the correct answers)