【题目】脱式计算.
28×25﹣240
125+18×23.
【答案】460;539
【解析】
试题分析:(1)在计算28×25时,把28看作7×4,运用乘法结合律简算;
(2)先算乘法,再算加法.
解:(1)28×25﹣240,
=7×4×25﹣240,
=7×(4×25)﹣240,
=7×100﹣240,
=700﹣240,
=460;
(2)125+18×23,
=125+414,
=539.
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