题目内容
脱式计算,能简算的要简算
-(
+
)
-
+
-
1-
+
-(
-
)
| 11 |
| 12 |
| 1 |
| 6 |
| 1 |
| 8 |
| 8 |
| 9 |
| 1 |
| 6 |
| 1 |
| 9 |
| 1 |
| 6 |
1-
| 1 |
| 4 |
| 3 |
| 4 |
| 1 |
| 2 |
| 3 |
| 4 |
| 3 |
| 8 |
分析:(1)、(3)和(4)先通分,再计算;(2)根据加法交换律和结合律进行简算.
解答:解:(1)
-(
+
),
=
-(
+
),
=
-
,
=
;
(2)
-
+
-
,
=(
+
)-(
+
),
=1-
,
=
;
(3)1-
+
,
=
+
,
=
;
(4)
-(
-
),
=
-(
-
),
=
-
,
=
.
| 11 |
| 12 |
| 1 |
| 6 |
| 1 |
| 8 |
=
| 22 |
| 24 |
| 4 |
| 24 |
| 3 |
| 24 |
=
| 22 |
| 24 |
| 7 |
| 24 |
=
| 5 |
| 8 |
(2)
| 8 |
| 9 |
| 1 |
| 6 |
| 1 |
| 9 |
| 1 |
| 6 |
=(
| 8 |
| 9 |
| 1 |
| 9 |
| 1 |
| 6 |
| 1 |
| 6 |
=1-
| 1 |
| 3 |
=
| 2 |
| 3 |
(3)1-
| 1 |
| 4 |
| 3 |
| 4 |
=
| 3 |
| 4 |
| 3 |
| 4 |
=
| 3 |
| 2 |
(4)
| 1 |
| 2 |
| 3 |
| 4 |
| 3 |
| 8 |
=
| 4 |
| 8 |
| 6 |
| 8 |
| 3 |
| 8 |
=
| 4 |
| 8 |
| 3 |
| 8 |
=
| 1 |
| 8 |
点评:分数的加减混合运算,一般先通分再计算,能简算的要简算.
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