题目内容
脱式计算:
|
|
5-
| ||||||||||||||||
|
|
分析:(1)(2)按照从左到右的顺序计算;
(3)根据减法的性质简算;
(4)先算小括号里面的减法,再算括号外的加法;
(5)根据加法交换律和结合律简算.
(3)根据减法的性质简算;
(4)先算小括号里面的减法,再算括号外的加法;
(5)根据加法交换律和结合律简算.
解答:解:(1)
-
+
,
=
+
,
=
;
(2)
+
-
,
=
-
,
=
;
(3)5-
-
,
=5-(
+
),
=5-1,
=4;
(4)
+(
-
),
=
+
,
=
;
(5)
+
+
+
,
=(
+
)+(
+
),
=1+1,
=2.
| 5 |
| 6 |
| 3 |
| 4 |
| 2 |
| 3 |
=
| 1 |
| 12 |
| 2 |
| 3 |
=
| 3 |
| 4 |
(2)
| 3 |
| 8 |
| 1 |
| 2 |
| 1 |
| 4 |
=
| 7 |
| 8 |
| 1 |
| 4 |
=
| 5 |
| 8 |
(3)5-
| 4 |
| 7 |
| 3 |
| 7 |
=5-(
| 4 |
| 7 |
| 3 |
| 7 |
=5-1,
=4;
(4)
| 2 |
| 3 |
| 3 |
| 5 |
| 1 |
| 2 |
=
| 2 |
| 3 |
| 1 |
| 10 |
=
| 23 |
| 30 |
(5)
| 4 |
| 9 |
| 3 |
| 10 |
| 5 |
| 9 |
| 7 |
| 10 |
=(
| 4 |
| 9 |
| 5 |
| 9 |
| 3 |
| 10 |
| 7 |
| 10 |
=1+1,
=2.
点评:本题考查了分数加减法混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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