题目内容
能简算的要简算 ①8-(+4÷) | ②(-×)÷ | ③÷[(-)÷] |
④+÷- | ⑤(1-)÷[(0.1+1.1)÷0.2] | ⑥×+4÷. |
解:①8-(+4÷)
=8-(+4×)
=8-(+6)
=8--6
=8-6-
=1;
②(-×)÷
=(-)×
=×
=;
③÷[(-)÷]
=÷[(-)×24]
=÷[×24-×24]
=÷5
=;
④+÷-
=+×-
=+-
=1;
⑤(1-)÷[(0.1+1.1)÷0.2]
=÷[1.2÷0.2]
=÷6
=;
⑥×+4÷
=+4×
=+14
=14.
分析:按计算顺序:有括号的先算括号,没括号的先算乘除后算加减.能用运算定律(如乘法分配律、加法结合律等)的,可以用定律简算.
点评:按四则运算顺序计算,能用运算定律的可以利用定律简算.
=8-(+4×)
=8-(+6)
=8--6
=8-6-
=1;
②(-×)÷
=(-)×
=×
=;
③÷[(-)÷]
=÷[(-)×24]
=÷[×24-×24]
=÷5
=;
④+÷-
=+×-
=+-
=1;
⑤(1-)÷[(0.1+1.1)÷0.2]
=÷[1.2÷0.2]
=÷6
=;
⑥×+4÷
=+4×
=+14
=14.
分析:按计算顺序:有括号的先算括号,没括号的先算乘除后算加减.能用运算定律(如乘法分配律、加法结合律等)的,可以用定律简算.
点评:按四则运算顺序计算,能用运算定律的可以利用定律简算.
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