21x19-19的,简便竖式方法?

2024-12-27 16:19:48
推荐回答(2个)
回答1:

21x19-19
=(21-1)x=19
=20x19
=380
希望能帮到你!

回答2:

简便计算
21x19-19
=(21-1)×19
=20×19
=380