题目内容
6.计算题:6.84×10.1
87×2.5+8.7×75
49.84-(51.17-12.56)÷27
(1.25+12.5+125)×0.8.
分析 (1)、(2)、(4)根据乘法分配律进行简算;
(3)先算小括号里面的减法,再算除法,最后算括号外面的减法.
解答 解:(1)6.84×10.1
=6.84×(10+0.1)
=6.84×10+6.84×0.1
=68.4+0.684
=69.084;
(2)87×2.5+8.7×75
=8.7×25+8.7×75
=8.7×(25+75)
=8.7×100
=870;
(3)49.84-(51.17-12.56)÷27
=49.84-38.61÷27
=49.84-1.43
=48.41;
(4)(1.25+12.5+125)×0.8
=1.25×0.8+12.5×0.8+125×0.8
=1+10+100
=111.
点评 考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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