原式=0.999+1-0.1+1-0.01+1-0.001-3=0.999+3-3-0.1-0.01-0.001=0.999-0.1-0.01-0.001=0.888 关键在于利用重复了两次了0.999,因为之前化简得出了减去0.1,0.01,0.001即是0.999的十分位、百分位、千分位的数值各减去1,...