Question

请数学计算解题高手来一下！

简便计算（写出过程，而且是递等式形式）
101×99×999+999
=

Answer 1

101×99×999+999
=（100+1）×（100-1）×999+999
=（100²-1+1）×999
=10000×999
=9990000

Answer 2

=(100+1)×(100-1)×999+999
=(100²-1)×999+999
=(10000-1+1)×999
=10000×999
=9990000

Answer 3

原式=（100+1）x99x999+999
=【（100+1）x99+1】x999
=(9900+99+1)X999
=10000X999
=9990000

Answer 4

=(100+1)(100-1)*999+999
=999*[(100+1)(100-1)+1]
=999*(10000-1+1)
=9990000

Answer 5

=(100+1)*(100-1)*999+999=[(10000-1)+1]*999=9990000