问题 解答题
怎样简便就怎样算:
(250+25)×4;

42×42+42×58;

99×57;

125×32.
答案

(1)(250+25)×4       

=250×4+25×4

=1000+100,

=1100;

(2)42×42+42×58,

=42×(42+58),

=42×100,

=4200;

(3)99×57,

=(100-1)×57,

=100×57-57×1,

=5700-57,

=5643;

 (4)125×32,

=125×8×4,

=1000×4,

=4000.

单项选择题 B1型题
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