用两个数码管显示0到99。十位数为0的时候，显示为空白。

用两个按键控制数值的加减，按一次K1数字加1，按一次K2数字减1，数值的范围是从0到99。

再用一个接近开关控制数字的减小，接近开关感应一次数字减1，减到0停止。

-With two digital display 0-99. 10-digit is 0, display is blank. Control values with addition and subtraction of two keys, K1 by a number plus 1, K2 by a number minus 1, the values range from 0 to 99. Then a figure close to the decrease of switching control, a proximity switch sensing the number by 1, reduced to 0 to stop.