1000分之999X1001的简便运算,

问题描述:

1000分之999X1001的简便运算,

999*1001=(1000-1)(1000+1)=1000000-1
1000分之999X1001=(1000000-1)/1000=1000-0.001=999.999

999/1000 *1001
=(1000-1)(1000+1)/1000
=(1000000-1)/1000
=999.999

1000分之999*1001 即 999*1001/1000
=(1000-1)*(1000+1)/1000
=(1000的平方-1的平方)/1000
=(1000000-1)/1000
=999999/1000
=999.999

999/1000×1001
=(1000+1)×999/1000
=999+999/1000
=999又999/1000