题目内容
(2007?银州区)计算下面的题,能简算的要用简便方法计算哟,并写出简算步骤.
①2.35-81÷27×0.45 ②125×
×0.8×
③3×(
+
)-
④[1-(
+
)]÷
.
①2.35-81÷27×0.45 ②125×
5 |
3 |
3 |
10 |
③3×(
2 |
15 |
1 |
12 |
2 |
5 |
1 |
4 |
3 |
8 |
1 |
4 |
分析:算式①③④根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的;
算式②可根据乘法交换律及结合律进行计算.
算式②可根据乘法交换律及结合律进行计算.
解答:解:①2.35-81÷27×0.45,
=2.35-3×0.45,
=2.35-1.35,
=1;
②125×
×0.8×
,
=(125×0.8)×(
×
),
=100×
,
=50;
③3×(
+
)-
,
=3×
-
,
=
-
,
=
;
④[1-(
+
)]÷
,
=[1-
]×4,
=
×4,
=
.
=2.35-3×0.45,
=2.35-1.35,
=1;
②125×
5 |
3 |
3 |
10 |
=(125×0.8)×(
5 |
3 |
3 |
10 |
=100×
1 |
2 |
=50;
③3×(
2 |
15 |
1 |
12 |
2 |
5 |
=3×
13 |
60 |
2 |
5 |
=
13 |
20 |
2 |
5 |
=
1 |
4 |
④[1-(
1 |
4 |
3 |
8 |
1 |
4 |
=[1-
5 |
8 |
=
3 |
8 |
=
3 |
2 |
点评:完成有关于分数的计算题目时要细心,关键要注意通分约分.
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