来自毛明的问题
巧算下面各题343+345+347+349+351115+120+125+130+135+140+1451+2+3+…+1002+4+6+…+1001001×9991001+1002+1003+…+2000646+647+648+649+650+651+652+653+654666×222+333×5561320÷33+1980÷33+495÷33．
巧算下面各题
343+345+347+349+351
115+120+125+130+135+140+145
1+2+3+…+100
2+4+6+…+100
1001×999
1001+1002+1003+…+2000
646+647+648+649+650+651+652+653+654
666×222+333×556
1320÷33+1980÷33+495÷33．
