999乘以999+999怎样简便
问题描述:
999乘以999+999怎样简便
答
999*(999+999)
=(1000-1)(2000-2)
=2000000-2000-2000+2
=1996002
答
结合率
就是 当成999*(999+1)= 999000
答
999*999+999
=999*(999+1)
=999*1000
=999000
*=乘