题目内容
你认为怎么简便就怎么算.
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5-
|
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|
|
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考点:分数的加法和减法,分数的四则混合运算
专题:运算顺序及法则
分析:(1)根据加法交换律和结合律进行简算;
(2)根据减法的性质进行简算;
(3)根据加法交换律和结合律进行简算;
(4)按照从左向右的顺序进行计算;
(5)先算小括号里面的加法,再算括号外面的加法;
(6)根据乘法分配律进行简算.
(2)根据减法的性质进行简算;
(3)根据加法交换律和结合律进行简算;
(4)按照从左向右的顺序进行计算;
(5)先算小括号里面的加法,再算括号外面的加法;
(6)根据乘法分配律进行简算.
解答:
解:(1)
+
+
+
=(
+
)+(
+
)
=1+1
=2;
(2)5-
-
=5-(
+
)
=5-1
=4;
(3)
-
+
+
=(
+
)+(
-
)
=1+
=1
;
(4)
-
+
=
+
=
;
(5)
+(
+
)
=
+
=
;
(6)
×20+
×20
=(
+
)×20
=1×20
=20.
11 |
12 |
5 |
8 |
3 |
8 |
1 |
12 |
=(
11 |
12 |
1 |
12 |
5 |
8 |
3 |
8 |
=1+1
=2;
(2)5-
3 |
7 |
4 |
7 |
=5-(
3 |
7 |
4 |
7 |
=5-1
=4;
(3)
3 |
4 |
2 |
5 |
1 |
4 |
3 |
5 |
=(
3 |
4 |
1 |
4 |
3 |
5 |
2 |
5 |
=1+
1 |
5 |
=1
1 |
5 |
(4)
5 |
6 |
1 |
4 |
1 |
3 |
=
7 |
12 |
1 |
3 |
=
11 |
12 |
(5)
23 |
28 |
13 |
14 |
2 |
7 |
=
23 |
28 |
17 |
14 |
=
57 |
14 |
(6)
2 |
5 |
3 |
5 |
=(
2 |
5 |
3 |
5 |
=1×20
=20.
点评: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定律简便计算.
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