19/20 × 199 × 19/20 怎么简便计算
问题描述：
19/20 × 199 × 19/20 怎么简便计算
答
19/20x199x19/20
=19x19/20x20x199
=381/400x200-381/400
=762-381/400
=761又(19/400)