9.9×9.9+19.9 简便计算
来源：学生作业帮助网 编辑：六六作业网 时间：2025/01/13 11:04:37
9.9×9.9+19.9简便计算9.9×9.9+19.9简便计算9.9×9.9+19.9简便计算9.9×9.9+19.9=9.9×（10-0.1）+19.9=9.9×10-9.9×0.1+19.9=9
9.9×9.9+19.9 简便计算
9.9×9.9+19.9 简便计算
9.9×9.9+19.9 简便计算
9.9×9.9+19.9
=9.9×（10-0.1）+19.9
=9.9×10-9.9×0.1+19.9
=99-0.99+19.9
=99+18.91
=117.91
(10-0.1)(10-0.1)+(20-0.1)，然后拆括号