简便计算 1.111×63+777×91 2.9999×7778+3333×6666 3.9999×9999+19999
1个回答

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 .