题目内容
脱式计算. 2-(
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|
|
分析:(1)先算加法,再算减法;
(2)根据加法交换律和结合律进行计算;
(3)、(4)按照从左向右的顺序进行计算.
(2)根据加法交换律和结合律进行计算;
(3)、(4)按照从左向右的顺序进行计算.
解答:解:
(1)2-(
+
),
=2-
,
=
;
(2)
+
-(
-
),
=
+
-
+
,
=(
-
)+(
-
),
=
+
,
=
;
(3)
-
+
,
=
+
,
=
;
(4)
+
-
,
=
-
,
=
.
(1)2-(
5 |
6 |
3 |
10 |
=2-
17 |
15 |
=
13 |
15 |
(2)
2 |
3 |
4 |
5 |
3 |
5 |
1 |
15 |
=
2 |
3 |
4 |
5 |
3 |
5 |
1 |
15 |
=(
2 |
3 |
1 |
15 |
4 |
5 |
3 |
5 |
=
3 |
5 |
1 |
5 |
=
4 |
5 |
(3)
5 |
6 |
7 |
9 |
3 |
4 |
=
1 |
18 |
3 |
4 |
=
29 |
36 |
(4)
1 |
3 |
1 |
4 |
1 |
5 |
=
7 |
12 |
1 |
5 |
=
23 |
60 |
点评:考查了分数四则混合运算,注意运算顺序和运算法则,然后再进一步计算.
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