问题 解答题
计算下面各题(能简算的要简算).
14
15
×(1-
2
7
5
9
×[
3
4
-(
7
16
-
1
4
)]
4
5
7
-(
5
7
+2.5)
1
8
×58+42÷8
5
12
×
1
9
+
7
9
×
5
12
+
5
12
÷9
9.84-1
3
7
-2
4
7
答案

(1)

14
15
×(1-
2
7
),

=

14
15
×1-
14
15
×
2
7

=

14
15
-
4
15

=

2
3

(2)

5
9
×[
3
4
-(
7
16
-
1
4
)],

=

5
9
×[
3
4
-
7
16
+
1
4
],

=

5
9
×[1-
7
16
],

=

5
9
×
9
16

=

5
16

(3)4

5
7
-(
5
7
+2.5),

=4

5
7
-
5
7
-2.5,

=4-2.5,

=1.5;

(4)

1
8
×58+42÷8,

=

1
8
×58+42×
1
8

=

1
8
×(58+42),

=

1
8
×100,

=12.5;

(5)

5
12
×
1
9
+
7
9
×
5
12
+
5
12
÷9,

=

5
12
×
1
9
+
7
9
×
5
12
+
5
12
×
1
9

=

5
12
×(
1
9
+
7
9
+
1
9
),

=

5
12
×1,

=

5
12

(6)9.84-1

3
7
-2
4
7

=9.84-(1

3
7
+2
4
7
),

=9.84-4,

=5.84.

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