题目内容
计算.(能简算的要简算)
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2-
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考点:分数的四则混合运算,运算定律与简便运算
专题:运算顺序及法则,运算定律及简算
分析:(1)按照从左向右的顺序进行计算;
(2)按照从左向右的顺序进行计算;
(3)根据加法交换律和结合律进行简算;
(4)根据减法的性质进行简算;
(5)先算小括号里面的减法,再算括号外面的减法;
(6)先算减法,再算加法.
(2)按照从左向右的顺序进行计算;
(3)根据加法交换律和结合律进行简算;
(4)根据减法的性质进行简算;
(5)先算小括号里面的减法,再算括号外面的减法;
(6)先算减法,再算加法.
解答:
解:(1)
+
+
=
+
=
;
(2)
+
-
=
-
=
;
(3)
+
+
-
=(
+
)+(
-
)
=1+
=1
;
(4)2-
-
=2-(
+
)
=2-
=1
;
(5)
-(
-
)
=
-
=
;
(6)
+(
-
)
=
+
=
.
3 |
8 |
5 |
6 |
1 |
4 |
=
29 |
24 |
1 |
4 |
=
35 |
24 |
(2)
4 |
5 |
7 |
10 |
11 |
20 |
=
3 |
2 |
11 |
20 |
=
19 |
20 |
(3)
11 |
19 |
7 |
18 |
8 |
19 |
1 |
18 |
=(
11 |
19 |
8 |
19 |
7 |
18 |
1 |
18 |
=1+
1 |
3 |
=1
1 |
3 |
(4)2-
1 |
9 |
2 |
3 |
=2-(
1 |
9 |
2 |
3 |
=2-
7 |
9 |
=1
2 |
9 |
(5)
7 |
8 |
3 |
7 |
1 |
14 |
=
7 |
8 |
5 |
14 |
=
29 |
56 |
(6)
5 |
6 |
1 |
3 |
1 |
4 |
=
5 |
6 |
1 |
12 |
=
11 |
12 |
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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