题目内容
计算下列各题(怎样简便就怎样算)
|
|
|
| ||||||||||||||||||||||||||
|
| x-(
|
考点:分数的四则混合运算
专题:运算顺序及法则
分析:(1)先算括号里的加法,再算括号外的减法;
(2)从左向右进行计算;
(3)运用加法的交换律、结合律进行简算;
(4)从左向右进行计算;
(5)运用加法的交换律、结合律进行简算;
(6)运用减法的性质进行简算;
(7)先化简方程,根据等式的性质,两边同时加上
求解.
(2)从左向右进行计算;
(3)运用加法的交换律、结合律进行简算;
(4)从左向右进行计算;
(5)运用加法的交换律、结合律进行简算;
(6)运用减法的性质进行简算;
(7)先化简方程,根据等式的性质,两边同时加上
19 |
30 |
解答:
解:(1)
-(
+
)
=
-
=
;
(2)
-
-
=
-
=
;
(3)
+
+
+
=(
+
)+(
+
)
=1+1
=2;
(4)
+
-
=
-
=
;
(5)
+
+
=
+(
+
)
=
+1
=1
;
(6)
-
-
=
-(
+
)
=
-1
=
;
(7)x-(
-
)=
x-
=
x-
+
=
+
x=
.
3 |
5 |
2 |
15 |
1 |
3 |
=
3 |
5 |
7 |
15 |
=
2 |
15 |
(2)
5 |
6 |
1 |
4 |
1 |
3 |
=
7 |
12 |
1 |
3 |
=
1 |
4 |
(3)
5 |
12 |
3 |
5 |
7 |
12 |
2 |
5 |
=(
5 |
12 |
7 |
12 |
3 |
5 |
2 |
5 |
=1+1
=2;
(4)
3 |
7 |
3 |
4 |
11 |
14 |
=
33 |
28 |
11 |
14 |
=
11 |
28 |
(5)
5 |
9 |
7 |
12 |
4 |
9 |
=
7 |
12 |
5 |
9 |
4 |
9 |
=
7 |
12 |
=1
7 |
12 |
(6)
15 |
11 |
3 |
8 |
5 |
8 |
=
15 |
11 |
3 |
8 |
5 |
8 |
=
15 |
11 |
=
4 |
11 |
(7)x-(
5 |
6 |
1 |
5 |
8 |
15 |
x-
19 |
30 |
8 |
15 |
x-
19 |
30 |
19 |
30 |
8 |
15 |
19 |
30 |
x=
7 |
6 |
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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