简便方法!
165+299 47×9+47 630÷18÷5 63×73-63×63
=165+300-1 =47×（9+1）吵笑姿 =630÷（18×5） =63×（73-63）升绝
=465-1 =47×10 =630÷90 =63×10
=464 =470 =7 =630
421-175-25 45×155×40
=421-（175+25）升斗 = 45×40×155
=421-200 =1800×5×31
=221 =9000×31
=279000
1.165+300-1
2.47*(9+1)
3.630/(18*5)
4.4*25*9
5.63*(73-63)
6.421-(175+25)
7.(31*9)*(5*5*40)