当ab12+9时,能个被9整除;即ab21各位数字之和能被9整除,a+b+2+1=a+b+3是9的倍数；当ab12-8时,能被8整除.ab04能被8整除,即4+2*0+4b=4*(1+b )是8的倍数；当b=1时,4*(1+b )=8,是8的整倍数,a+b+3=9时,a=5 即：5112当b=3时...