Question

90✖️42➖90点简便运算杂做的谢谢

90✖️42➖90点简便运算杂做的谢谢

Answer 1

90x（42一1）＝90Ⅹ41＝90x（40十1）＝3600十90＝3690

Answer 2

=90乘以（42-1）=90乘以41=90乘以（40+1）=3600+90=3690

Answer 3

原式=90*(42-1)=90*41=3690

Answer 4

90X42-90
=90X(42-1)
=90X(40+1)
=3600+90
=3690。

Answer 5

=90X（42-1）
=90X41
=90X（40+1）
=90X40+90X1
=3600+90
=3690