题目内容
计算下面各题,(能简算的要简算)
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分析:(1)运用减法的性质以及加法交换律与结合律简算;
(2)(5)通分计算;
(3)(4)(6)运用加法交换律与结合律简算.
(2)(5)通分计算;
(3)(4)(6)运用加法交换律与结合律简算.
解答:解:(1)
-(
-
),
=(
-
)-
,
=
-
,
=
;
(2)
+
-
,
=
+
-
,
=
;
(3)
+(
+
),
=
+
+
,
=(
+
)+
,
=1+
,
=
;
(4)
+
-
+
,
=(
+
)+(
-
),
=1+
,
=1
;
(5)
+
+
,
=
+
+
,
=
;
(6)
+
-
+
,
=(
-
)+(
+
),
=
+1,
=1
.
4 |
5 |
3 |
11 |
1 |
5 |
=(
4 |
5 |
1 |
5 |
3 |
11 |
=
3 |
5 |
3 |
11 |
=
18 |
55 |
(2)
5 |
18 |
3 |
20 |
2 |
9 |
=
50 |
180 |
27 |
180 |
40 |
180 |
=
37 |
180 |
(3)
8 |
11 |
6 |
7 |
3 |
11 |
=
8 |
11 |
6 |
7 |
3 |
11 |
=(
8 |
11 |
3 |
11 |
6 |
7 |
=1+
6 |
7 |
=
6 |
7 |
(4)
5 |
6 |
7 |
20 |
3 |
20 |
1 |
6 |
=(
5 |
6 |
1 |
6 |
7 |
20 |
3 |
20 |
=1+
1 |
5 |
=1
1 |
5 |
(5)
3 |
8 |
5 |
6 |
1 |
3 |
=
9 |
24 |
20 |
24 |
8 |
24 |
=
37 |
24 |
(6)
5 |
17 |
7 |
8 |
4 |
17 |
1 |
8 |
=(
5 |
17 |
4 |
17 |
7 |
8 |
1 |
8 |
=
1 |
17 |
=1
1 |
17 |
点评:此题主要考查分数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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