题目内容
灵活计算,(能简便计算的要用简便方法计算)
|
35×(1--
| ||||||||||||
|
3.4÷[(1.25+0.45)×23]. |
分析:①②④按照分数的四则混合运算的顺序进行计算,先做乘除后做加减.
③运用乘法的分配律进行计算,使计算更加简便.
③运用乘法的分配律进行计算,使计算更加简便.
解答:解:①
×
÷
×
,
=
×
×
×
,
=
;
②35×(1-
)÷
,
=35×
×
,
=48;
③
×
+
÷13,
=
×
+
×
,
=
×(
+
),
=
;
④3.4÷[(1.25+0.45)×23],
=3.4÷[1.7×23],
=3.4÷1.7÷23,
=2÷23,
=
.
4 |
5 |
8 |
21 |
12 |
11 |
7 |
22 |
=
4 |
5 |
8 |
21 |
7 |
22 |
11 |
12 |
=
4 |
45 |
②35×(1-
3 |
7 |
5 |
12 |
=35×
4 |
7 |
12 |
5 |
=48;
③
7 |
8 |
12 |
13 |
7 |
8 |
=
7 |
8 |
12 |
13 |
7 |
8 |
1 |
13 |
=
7 |
8 |
12 |
13 |
1 |
13 |
=
7 |
8 |
④3.4÷[(1.25+0.45)×23],
=3.4÷[1.7×23],
=3.4÷1.7÷23,
=2÷23,
=
2 |
23 |
点评:本题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律简便计算.
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