题目内容
脱式计算(能简算的要简算).
(1)
+
+
(2)
-
-
(3)
+
-
(4)
+
-
(5)
+
+
(6)10-
-
.
(1)
5 |
6 |
2 |
9 |
7 |
18 |
(2)
2 |
3 |
1 |
4 |
1 |
6 |
(3)
3 |
4 |
2 |
5 |
11 |
20 |
(4)
7 |
11 |
1 |
2 |
3 |
11 |
(5)
3 |
8 |
1 |
4 |
5 |
12 |
(6)10-
4 |
15 |
4 |
5 |
分析:(4)运用加法交换律简算;(6)根据连续减去两个数等于减去这两个数的和简算;其它题目通分后按照从左向右的顺序计算.
解答:解:(1)
+
+
,
=
+
+
,
=
+
,
=
;
(2)
-
-
,
=
-
-
,
=
-
,
=
;
(3)
+
-
,
=
+
-
,
=
-
,
=
;
(4)
+
-
,
=
-
+
,
=
+
,
=
;
(5)
+
+
,
=
+
+
,
=
+
,
=
;
(6)10-
-
,
=10-(
+
),
=10-1
;
=8
.
5 |
6 |
2 |
9 |
7 |
18 |
=
15 |
18 |
4 |
18 |
7 |
18 |
=
19 |
18 |
7 |
18 |
=
13 |
9 |
(2)
2 |
3 |
1 |
4 |
1 |
6 |
=
8 |
12 |
3 |
12 |
2 |
12 |
=
5 |
12 |
2 |
12 |
=
1 |
4 |
(3)
3 |
4 |
2 |
5 |
11 |
20 |
=
15 |
20 |
8 |
20 |
11 |
20 |
=
23 |
20 |
11 |
20 |
=
3 |
5 |
(4)
7 |
11 |
1 |
2 |
3 |
11 |
=
7 |
11 |
3 |
11 |
1 |
2 |
=
4 |
11 |
1 |
2 |
=
19 |
22 |
(5)
3 |
8 |
1 |
4 |
5 |
12 |
=
9 |
24 |
6 |
24 |
10 |
24 |
=
15 |
24 |
10 |
24 |
=
25 |
24 |
(6)10-
4 |
15 |
4 |
5 |
=10-(
4 |
15 |
4 |
5 |
=10-1
1 |
15 |
=8
14 |
15 |
点评:本题考查了基本的分数加减混合运算,关键是通分,注意结果化成最简分数.
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