简便计算 下列横式

333*666+778*999
=333*3*222+778*999
=999*222+778*999
=999*（222+778）
=999*1000
=999000

333*666+778*999
=3*111*6*111+(777+1)*999
=18*111^2+777*999+999
=18*111^2+63*111^2+9*111
=(18+63)*111^2+9*111
=81*111^2+9*111
=9*111*(9*111+1)
=999*10000
=9990000.

333X666+778X999
=333*666+778*（333+333+333）
=333*666+778*333+778*333+778*333
=（666+778+778+778）*333
=3000*333
=999000

解:333*666+778*999
=333*3*222+778*999
=999*222+778*999
=999*(222+778)
=999*1000
=999000

用到了乘法结合率和交换率

谢谢

333*666+778*999
=333*222*3+778*3*333
=333(222*3+778*3)
=333((222+778)*3)
=333(1000*3)
=333*3000
=999000

333X666+778X999=333*(666+3*778)=333*(666+3*2*389)
=333*6*(111+389)=333*6*500=333*3000=999000