题目内容
能简算的要简算
| 2-
|
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|
|
|
考点:分数的加法和减法,分数的简便计算
专题:运算顺序及法则
分析:(1)根据加法交换律进行简算;
(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)根据减法的性质进行简算;
(5)根据减法的性质进行简算;
(6)按照从左向右的顺序进行计算
(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)根据减法的性质进行简算;
(5)根据减法的性质进行简算;
(6)按照从左向右的顺序进行计算
解答:
解:(1)
-
+
=
+
-
=
-
=
;
(2)2-
-
=2-(
+
)
=2-
=
;
(3)
-
-
+
=(
+
)-(
+
)
=1-
=
;
(4)
-(
+
)
=
-
-
=
-
-
=1-
=
;
(5)
-(
-
)
=
-
+
=
+
-
=1-
=
;
(6)
+
-
=
-
=
.
7 |
8 |
4 |
7 |
3 |
8 |
=
7 |
8 |
3 |
8 |
4 |
7 |
=
5 |
4 |
4 |
7 |
=
19 |
28 |
(2)2-
2 |
3 |
7 |
12 |
=2-(
2 |
3 |
7 |
12 |
=2-
5 |
4 |
=
3 |
4 |
(3)
5 |
11 |
1 |
4 |
1 |
4 |
6 |
11 |
=(
5 |
11 |
6 |
11 |
1 |
4 |
1 |
4 |
=1-
1 |
2 |
=
1 |
2 |
(4)
9 |
7 |
3 |
4 |
2 |
7 |
=
9 |
7 |
3 |
4 |
2 |
7 |
=
9 |
7 |
2 |
7 |
3 |
4 |
=1-
3 |
4 |
=
1 |
4 |
(5)
9 |
19 |
8 |
9 |
10 |
19 |
=
9 |
19 |
8 |
9 |
10 |
19 |
=
9 |
19 |
10 |
19 |
8 |
9 |
=1-
8 |
9 |
=
1 |
9 |
(6)
8 |
9 |
1 |
6 |
3 |
4 |
=
19 |
18 |
3 |
4 |
=
11 |
36 |
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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