题目内容
| 5 |
| 12 |
| 4 |
| 9 |
| 7 |
| 12 |
| 5 |
| 9 |
| 5 |
| 6 |
| 1 |
| 5 |
| 1 |
| 6 |
1
| 7 |
| 8 |
| 4 |
| 5 |
| 1 |
| 5 |
| 2 |
| 7 |
| 3 |
| 14 |
| 4 |
| 21 |
| 7 |
| 8 |
| 1 |
| 3 |
| 1 |
| 12 |
| 3 |
| 4 |
| 2 |
| 3 |
| 1 |
| 6 |
分析:(1)运用加法交换律和加法结合律简算;
(2)(3)根据减法的性质简算;
(4)(6)按照从左到右的顺序计算;
(5)先算小括号里面的减法,再算括号外的减法.
(2)(3)根据减法的性质简算;
(4)(6)按照从左到右的顺序计算;
(5)先算小括号里面的减法,再算括号外的减法.
解答:解:(1)
+
+
+
,
=(
+
)+(
+
),
=1+1,
=2;
(2)
-(
+
),
=
-
-
,
=
-
,
=
;
(3)1
-
-
,
=1
-(
+
),
=1
-1,
=
;
(4)
+
+
,
=
+
,
=
;
(5)
-(
-
),
=
-
,
=
;
(6)
-
+
,
=
+
,
=
.
| 5 |
| 12 |
| 4 |
| 9 |
| 7 |
| 12 |
| 5 |
| 9 |
=(
| 5 |
| 12 |
| 7 |
| 12 |
| 4 |
| 9 |
| 5 |
| 9 |
=1+1,
=2;
(2)
| 5 |
| 6 |
| 1 |
| 5 |
| 1 |
| 6 |
=
| 5 |
| 6 |
| 1 |
| 6 |
| 1 |
| 5 |
=
| 2 |
| 3 |
| 1 |
| 5 |
=
| 7 |
| 15 |
(3)1
| 7 |
| 8 |
| 4 |
| 5 |
| 1 |
| 5 |
=1
| 7 |
| 8 |
| 4 |
| 5 |
| 1 |
| 5 |
=1
| 7 |
| 8 |
=
| 7 |
| 8 |
(4)
| 2 |
| 7 |
| 3 |
| 14 |
| 4 |
| 21 |
=
| 1 |
| 2 |
| 4 |
| 21 |
=
| 29 |
| 42 |
(5)
| 7 |
| 8 |
| 1 |
| 3 |
| 1 |
| 12 |
=
| 7 |
| 8 |
| 1 |
| 12 |
=
| 19 |
| 24 |
(6)
| 3 |
| 4 |
| 2 |
| 3 |
| 1 |
| 6 |
=
| 1 |
| 12 |
| 2 |
| 12 |
=
| 1 |
| 4 |
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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