题目内容
递等式计算.(能简便的要简算)
(1)3÷
(2)5.4-(0.4+12×0.25)
(3)
(4)
(5)
(6).
解:(1)3÷,
=9+,
=9;
(2)5.4-(0.4+12×0.25),
=5.4-(0.4+3),
=5.4-3.4,
=2;
(3),
=(10)-(5.89+4.11),
=11-10,
=1;
(4),
=1×(0.875+1),
=12,
=3;
(5),
=1,
=3;
(6),
=8[1.25+×12],
=8[1.25+7],
=88.25,
=1.
分析:(1)(2)(5)(6)依据四则运算计算方法,先算第二级运算,再算第一级运算,如果只含有同一级运算,按照从左到右顺序计算,有括号先算括号里面的解答,
(3)运用加法交换律,以及减法性质解答,
(4)运用乘法分配律解答.
点评:本题考查知识点:(1)四则运算计算方法,(2)简便算法的运用.
=9+,
=9;
(2)5.4-(0.4+12×0.25),
=5.4-(0.4+3),
=5.4-3.4,
=2;
(3),
=(10)-(5.89+4.11),
=11-10,
=1;
(4),
=1×(0.875+1),
=12,
=3;
(5),
=1,
=3;
(6),
=8[1.25+×12],
=8[1.25+7],
=88.25,
=1.
分析:(1)(2)(5)(6)依据四则运算计算方法,先算第二级运算,再算第一级运算,如果只含有同一级运算,按照从左到右顺序计算,有括号先算括号里面的解答,
(3)运用加法交换律,以及减法性质解答,
(4)运用乘法分配律解答.
点评:本题考查知识点:(1)四则运算计算方法,(2)简便算法的运用.
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