Question

0.9＋99×0.9 脱式计算写下来谢谢

Answer 1

0.9+99×0.9=0.9×1+0.9×99=0.9×100=90

Answer 2

0.9+99×0.9
=0.9×1+99×0.9
=（1+99）×0.9
=100×0.9
=90

Answer 3

 

Answer 4

=0.9+90-0.9
=90

Answer 5