⑴ 78乘以99的简便计算
78乘以99的简便计算=78x（100-1）=78x100-78=7800-78=7722
⑵ 99×78简便计算
99×78＝（100-1）×78＝100×78-1×78＝7800-78＝7722
⑶ 99乘78用简便
99乘78=(100-1)x78=100x78-78=7800-78=7722不明白可以追问！满意请点击下面的【选为满意回答】按钮，O(∩_∩)O谢谢