题目内容
脱式计算,能简算的要简算
|
|
|
|
分析:(1)根据加法结合律简算;
(2)(3)根据减法的性质简算;
(4)根据加法交换律和结合律简算.
(2)(3)根据减法的性质简算;
(4)根据加法交换律和结合律简算.
解答:解:(1)
+
-
,
=
+(
-
),
=
+
,
=
;
(2)
-(
+
),
=
-
-
,
=1-
,
=
;
(3)
-(
-
),
=
-
+
,
=
+
,
=
;
(4)
+
+
-
,
=(
+
)+(
-
),
=1+
,
=1
.
| 2 |
| 3 |
| 4 |
| 5 |
| 3 |
| 10 |
=
| 2 |
| 3 |
| 4 |
| 5 |
| 3 |
| 10 |
=
| 2 |
| 3 |
| 1 |
| 2 |
=
| 7 |
| 6 |
(2)
| 11 |
| 8 |
| 5 |
| 6 |
| 3 |
| 8 |
=
| 11 |
| 8 |
| 3 |
| 8 |
| 5 |
| 6 |
=1-
| 5 |
| 6 |
=
| 1 |
| 6 |
(3)
| 6 |
| 7 |
| 11 |
| 14 |
| 1 |
| 2 |
=
| 6 |
| 7 |
| 11 |
| 14 |
| 1 |
| 2 |
=
| 1 |
| 14 |
| 1 |
| 2 |
=
| 4 |
| 7 |
(4)
| 5 |
| 9 |
| 6 |
| 11 |
| 4 |
| 9 |
| 4 |
| 11 |
=(
| 5 |
| 9 |
| 4 |
| 9 |
| 6 |
| 11 |
| 4 |
| 11 |
=1+
| 2 |
| 11 |
=1
| 2 |
| 11 |
点评:本题考查了基本的分数的加减混合运算,要注意分析数据,选择合适的简算方法简算.
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