79+81+84+81＝3251079000÷325＝3320这四个括号里填相同的数3320
()×79+()×81+()×84+()×81＝1079000()×[79+81+84+81]=1079000()×[160+165]=1079000()×325=1079000()=1079000÷325()=3320
