题目内容
计算下面各题. 42÷(÷) | (-)÷ | ×+÷3 |
12×(÷) | ×7+×7 | 9×÷9×. |
解:(1)42÷(÷),
=42,
=15;
(2)(-)÷,
=,
=;
(3)×+÷3,
=×(),
=×1,
=;
(4)12×(÷),
=12×,
=56;
(5)×7+×7,
=(+)×7,
=1×7,
=7;
(6)9×÷9×,
=1÷9×,
=×,
=.
分析:(1)(2)(4)先算括号里面的,再算括号外面的,
(3)(5)运用乘法分配律计算,
(6)按照从左到右的顺序计算.
点评:解答此题时要按照四则运算计算方法正确进行计算,有简便算法的注意选择并运用正确的简便算法,关键是结果的正确性.
=42,
=15;
(2)(-)÷,
=,
=;
(3)×+÷3,
=×(),
=×1,
=;
(4)12×(÷),
=12×,
=56;
(5)×7+×7,
=(+)×7,
=1×7,
=7;
(6)9×÷9×,
=1÷9×,
=×,
=.
分析:(1)(2)(4)先算括号里面的,再算括号外面的,
(3)(5)运用乘法分配律计算,
(6)按照从左到右的顺序计算.
点评:解答此题时要按照四则运算计算方法正确进行计算,有简便算法的注意选择并运用正确的简便算法,关键是结果的正确性.
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