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用简便方法计算下面各题.25+914+514=14+37+34+47=1120+49+920−49=67−(47+114)=1118−58+1718−38=6−27−57=916−(34−316)=27+(35+17)−15=

题目详情
用简便方法计算下面各题.
2
5
+
9
14
+
5
14
=
1
4
+
3
7
+
3
4
+
4
7
=
11
20
+
4
9
+
9
20
4
9
=
6
7
−(
4
7
+
1
14
)=
11
18
5
8
+
17
18
3
8
=
6−
2
7
5
7
=
9
16
−(
3
4
3
16
)=
2
7
+(
3
5
+
1
7
)−
1
5
=
▼优质解答
答案和解析
(1)
2
5
+
9
14
+
5
14

=
2
5
+(
9
14
+
5
14
),
=
2
5
+1,
=1
2
5


(2)
1
4
+
3
7
+
3
4
+
4
7

=(
1
4
+
3
4
)+(
3
7
+
4
7
),
=1+1,
=2;

(3)
11
20
+
4
9
+
9
20
-
4
9

=(
11
20
+
9
20
)+(
4
9
-
4
9
),
=1+0,
=1;

(4)
6
7
−(
4
7
+
1
14
),
=
6
7
-
4
7
-
1
14

=
2
7
-
1
14

=
3
14


(5)
11
18
-
5
8
+
17
18
-
3
8

=(
11
18
+
17
18
)-(
5
8
+
3
8
),
=1
5
9
-1,
=
5
9


(6)6−
2
7
5
7

=6-(
2
7
+
5
7
),
=6-1,
=5;

(7)
9
16
-(
3
4
-
3
16
),
=
9
16
-
3
4
+
3
16

=
9
16
+
3
16
-
3
4

=
3
4
-
3
4

=0;

(8)
2
7
+(
3
5
+
1
7
)−
1
5

=
2
7
+
3
5
+
1
7
-
1
5

=(
2
7
+
1
7
)+(
3
5
-
1
5
),
=
3
7
+
2
5

=
29
35