9.9×9+9.9怎么用简便的方法算(递等式计算)!!

2025-02-28 04:23:54
推荐回答(4个)
回答1:

9.9×9+9.9
=9.9×(9+1)
=9.9×10
=99

回答2:

9.9×9+9.9
=9.9×(9+1)
=99

回答3:

9.9×9+9.9
=9.9×9+9.9×1
=9.9×(9+1)
=9.9×10
=99

回答4:

9.9x9+9.9
=9.9x(9+1)
=9.9x10
=99