题目内容
脱式计算(能简便的要用简便方法计算)
(1)
|
(2)
|
(3)
| ||||||||||||||||||
(4)7-(
|
(5)
|
(6)
|
分析:(1)(2)(4)(5)依据分数四则运算计算顺序即可解答,
(3)依据减法性质解答,
(6)运用加法交换律和结合律解答.
(3)依据减法性质解答,
(6)运用加法交换律和结合律解答.
解答:解:(1)
+
+
,
=
+
,
=
;
(2)
+
-
,
=
+
,
=1;
(3)
+
-
,
=
-
,
=
;
(4)7-(
-
),
=7-
,
=6
;
(5)
-(
+
),
=
-
,
=
;
(6)
+
-
+
,
=(
-
)+(
+
),
=0+
,
=
.
1 |
6 |
1 |
5 |
1 |
3 |
=
11 |
30 |
1 |
3 |
=
7 |
10 |
(2)
7 |
12 |
1 |
6 |
1 |
4 |
=
3 |
4 |
1 |
4 |
=1;
(3)
8 |
11 |
7 |
15 |
8 |
15 |
=
8 |
11 |
1 |
15 |
=
109 |
165 |
(4)7-(
3 |
4 |
1 |
5 |
=7-
11 |
20 |
=6
9 |
20 |
(5)
4 |
5 |
4 |
15 |
1 |
3 |
=
4 |
5 |
9 |
15 |
=
1 |
5 |
(6)
4 |
7 |
5 |
21 |
4 |
7 |
2 |
21 |
=(
4 |
7 |
4 |
7 |
5 |
21 |
2 |
21 |
=0+
1 |
3 |
=
1 |
3 |
点评:本题考查知识点:(1)按照四则运算计算顺序正确进行计算,(2)正确运用简便算法解决问题.
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