题目内容
脱式计算,能简便的要简便.
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考点:分数的四则混合运算,分数的简便计算
专题:运算顺序及法则
分析:(1)从左向右进行计算;
(2)运用加法的交换律进行简算;
(3)先去括号,先减去
,再减去
;
(4)运用减法的性质进行简算;
(5)运用加法交换律、结合律进行简算;
(6)运用加法交换律、结合律,减法的性质进行简算.
(2)运用加法的交换律进行简算;
(3)先去括号,先减去
3 |
5 |
4 |
24 |
(4)运用减法的性质进行简算;
(5)运用加法交换律、结合律进行简算;
(6)运用加法交换律、结合律,减法的性质进行简算.
解答:
解:(1)
+
+
=
+
=
;
(2)
+
+
=
+
+
=1+
=1
;
(3)
-(
+
)
=
-
-
=
-
-
=1-
=
;
(4)
-
-
=
-(
+
)
=
-1
=
;
(5)
+
-
+
=(
-
)+(
+
)
=0+
=
;
(6)
-
+
-
=(
+
)-(
+
)
=
-1
=
.
3 |
4 |
5 |
7 |
1 |
2 |
=
41 |
28 |
1 |
2 |
=
55 |
28 |
(2)
4 |
5 |
2 |
3 |
1 |
5 |
=
4 |
5 |
1 |
5 |
2 |
3 |
=1+
2 |
3 |
=1
2 |
3 |
(3)
8 |
5 |
4 |
21 |
3 |
5 |
=
8 |
5 |
4 |
21 |
3 |
5 |
=
8 |
5 |
3 |
5 |
4 |
21 |
=1-
4 |
21 |
=
17 |
24 |
(4)
9 |
5 |
2 |
7 |
5 |
7 |
=
9 |
5 |
2 |
7 |
5 |
7 |
=
9 |
5 |
=
4 |
5 |
(5)
12 |
13 |
7 |
11 |
12 |
13 |
7 |
11 |
=(
12 |
13 |
12 |
13 |
7 |
11 |
7 |
11 |
=0+
14 |
11 |
=
14 |
11 |
(6)
4 |
7 |
1 |
18 |
5 |
7 |
17 |
18 |
=(
4 |
7 |
5 |
7 |
1 |
18 |
17 |
18 |
=
9 |
7 |
=
2 |
7 |
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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