简便计算 :
1.111×63+777×91
=111*(63+7*91)
=111*700
=77700
2.9999×7778+3333×6666
=9999*(7778+2222)
=9999*10000
=99990000
3.9999×9999+19999
=9999*(10000-1)+19999
=99990000-9999+19999
=99990000+10000
=10000 0000 .
简便计算 :
1.111×63+777×91
=111*(63+7*91)
=111*700
=77700
2.9999×7778+3333×6666
=9999*(7778+2222)
=9999*10000
=99990000
3.9999×9999+19999
=9999*(10000-1)+19999
=99990000-9999+19999
=99990000+10000
=10000 0000 .