9×101×101×10001
=9×(100+1)×(100+1)×(10000+1)
=(900+9)×(100+1)×(10000+1)
=(90000+900+900+9)×(10000+1)
=900000000+9000000+9000000+90000+90000+900+900+9
= 918181809
9×101×101×10001
=9×(100+1)×(100+1)×(10000+1)
=(900+9)×(100+1)×(10000+1)
=(90000+900+900+9)×(10000+1)
=900000000+9000000+9000000+90000+90000+900+900+9
=918181809