问题 解答题
用递等式计算,能简算的要简算
(1)(
5
12
+
1
9
+
3
8
)×72

(2)(2-
3
4
×
4
5
)÷(
1
12
+
4
15
)
(3)5
2
5
-(1
5
6
+3
3
10
)
(4)[(2
1
3
+4.8÷1
3
5
)-4
1
6
]×1
1
2
答案

解(1)(

5
12
+
1
9
+
3
8
)×72,

=72×

5
12
+72×
1
9
+
3
8
×
72,

=30+8+27,

=65;

(2)(2-

3
4
×
4
5
)÷(
1
12
+
4
15
),

=(2-

3
5
)÷(
5
60
+
16
60
),

=

7
5
×
60
21

=4;

(3)5

2
5
-(1
5
6
+3
3
10
),

=5

12
30
-(1
25
30
+3
9
30
),

=4

42
30
-4
34
30

=

4
15

(4)[(2

1
3
+4.8÷1
3
5
)-4
1
6
1
1
2

=[(2

1
3
+3)-4
1
6
3
2

=[5

2
6
-4
1
6
3
2

=

7
6
×
3
2

=1

3
4

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