题目内容
【题目】简便运算.
(+)×15×17
68﹣7.5+32﹣2.5
﹣(﹣)
【答案】10;47;90;
【解析】
试题分析:(1)+2+3.25+3,把化成0.75,运用加法交换律和结合律简算;
(2)(+)×15×17,运用乘法分配律简算;
(3)68﹣7.5+32﹣2.5,运用加法结合律和减法的运算性质进行简算;
(4)﹣(﹣),根据减法的运算性质进行简算.
解:(1)+2+3.25+3,
=(0.75+3.25)+(2+3),
=4+6,
=10;
(2)(+)×15×17,
=(15×15)×17,
=(1+)×17,
=1×1717,
=17+30,
=47;
(3)68﹣7.5+32﹣2.5,
=68+32﹣(7.5+2.5),
=100﹣10,
=90;
(4)﹣(﹣),
=﹣,
=,
=.
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