9999乘9999的简便计算怎么写?

问题描述:

9999乘9999的简便计算怎么写?

9999*(10000-1)=99990000-9999

9999X9999
=(10000-1)X9999
=99990000-9999
=99980001

9999*9999
=(10000-1)*(10000-1)=10000*10000-2*10000*1+1*1
=.....下面的很简单了吧

9999×9999
=(10000-1)²
=100000000-20000+1
=999980001

9999x9999
=(10000-1)x9999
=99990000-9999
=99980001