题目内容
下面各题怎样算简便就怎样算.
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分析:(1)按照从左到右的顺序计算;
(2)根据加法结合律简算;
(3)根据减法的性质简算;
(4)(6)根据加法交换律和结合律简算;
(5)根据加法交换律和减法的性质简算.
(2)根据加法结合律简算;
(3)根据减法的性质简算;
(4)(6)根据加法交换律和结合律简算;
(5)根据加法交换律和减法的性质简算.
解答:解:(1)
+
-
=
+
-
=
;
(2)
+
-
=
+(
-
)
=
+
=
;
(3)
-(
-
)
=
-
+
=
+
-
=
-
=
;
(4)
+(
-
)
=
-
+
=
+
=
;
(5)
-
+
-
=(
+
)-(
+
)
=1-1
=0;
(6)
+
+
+
=(
+
)+(
+
)
=
+
=
.
| 2 |
| 5 |
| 1 |
| 6 |
| 1 |
| 3 |
=
| 12 |
| 30 |
| 5 |
| 30 |
| 10 |
| 30 |
=
| 7 |
| 30 |
(2)
| 3 |
| 4 |
| 5 |
| 6 |
| 1 |
| 6 |
=
| 3 |
| 4 |
| 5 |
| 6 |
| 1 |
| 6 |
=
| 3 |
| 4 |
| 2 |
| 3 |
=
| 17 |
| 12 |
(3)
| 13 |
| 15 |
| 1 |
| 4 |
| 1 |
| 15 |
=
| 13 |
| 15 |
| 1 |
| 4 |
| 1 |
| 15 |
=
| 13 |
| 15 |
| 1 |
| 15 |
| 1 |
| 4 |
=
| 14 |
| 15 |
| 1 |
| 4 |
=
| 41 |
| 60 |
(4)
| 5 |
| 7 |
| 1 |
| 3 |
| 3 |
| 14 |
=
| 5 |
| 7 |
| 3 |
| 14 |
| 1 |
| 3 |
=
| 1 |
| 2 |
| 1 |
| 3 |
=
| 5 |
| 6 |
(5)
| 2 |
| 5 |
| 3 |
| 8 |
| 3 |
| 5 |
| 5 |
| 8 |
=(
| 2 |
| 5 |
| 3 |
| 5 |
| 3 |
| 8 |
| 5 |
| 8 |
=1-1
=0;
(6)
| 8 |
| 27 |
| 4 |
| 9 |
| 3 |
| 27 |
| 4 |
| 9 |
=(
| 8 |
| 27 |
| 3 |
| 27 |
| 4 |
| 9 |
| 4 |
| 9 |
=
| 11 |
| 27 |
| 8 |
| 9 |
=
| 35 |
| 27 |
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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