题目内容
计算下列各题,怎样简便就怎样算.
+
-
+
+
+
+(
-
)
-
-
+
-
+
+
+
.
1 |
2 |
1 |
3 |
1 |
4 |
3 |
7 |
3 |
8 |
4 |
7 |
1 |
8 |
5 |
9 |
5 |
6 |
1 |
2 |
9 |
7 |
5 |
8 |
3 |
8 |
5 |
7 |
2 |
3 |
9 |
14 |
3 |
4 |
2 |
5 |
5 |
4 |
3 |
5 |
分析:(1)按照从左向右的顺序进行计算;
(2)根据加法交换律和结合律进行简算;
(3)先算减法,再算加法;
(4)根据减法的性质进简算;
(5)按照从左向右的顺序进行计算;
(6)根据加法交换律和结合律进行简算.
(2)根据加法交换律和结合律进行简算;
(3)先算减法,再算加法;
(4)根据减法的性质进简算;
(5)按照从左向右的顺序进行计算;
(6)根据加法交换律和结合律进行简算.
解答:解:
(1)
+
-
,
=
-
,
=
;
(2)
+
+
+
,
=(
+
)+(
+
),
=1+
,
=1
;
(3)
+(
-
),
=
+
,
=
;
(4)
-
-
,
=
-(
+
),
=
-1,
=
;
(5)
+
-
,
=
-
,
=
;
(6)
+
+
+
,
=(
+
)+(
+
),
=2+1,
=3.
(1)
1 |
2 |
1 |
3 |
1 |
4 |
=
5 |
6 |
1 |
4 |
=
7 |
12 |
(2)
3 |
7 |
3 |
8 |
4 |
7 |
1 |
8 |
=(
3 |
7 |
4 |
7 |
3 |
8 |
1 |
8 |
=1+
1 |
2 |
=1
1 |
2 |
(3)
5 |
9 |
5 |
6 |
1 |
2 |
=
5 |
9 |
1 |
3 |
=
8 |
9 |
(4)
9 |
7 |
5 |
8 |
3 |
8 |
=
9 |
7 |
5 |
8 |
3 |
8 |
=
9 |
7 |
=
2 |
7 |
(5)
5 |
7 |
2 |
3 |
9 |
14 |
=
29 |
21 |
9 |
14 |
=
31 |
42 |
(6)
3 |
4 |
2 |
5 |
5 |
4 |
3 |
5 |
=(
3 |
4 |
5 |
4 |
2 |
5 |
3 |
5 |
=2+1,
=3.
点评:此题主要考查分数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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