问题 解答题
脱式计算,注意使用简便算法.
5
18
÷(
5
6
+
5
9
)
5
7
+
2
7
×(
3
10
+
2
5
)
(
1
4
-
1
20
)×40
4
9
÷
3
8
4
7
+9×
3
7
+9
15
22
÷[
1
4
÷(
1
2
-
1
3
)]
答案

(1)

5
18
÷(
5
6
+
5
9

=

5
18
÷
25
18

=

1
5

(2)

5
7
+
2
7
×(
3
10
+
2
5

=

5
7
+
2
7
×
7
10

=

5
7
+
1
5

=

32
35

(3)(

1
4
-
1
20
)×40

=

1
4
×40-
1
20
×40

=10-2

=8;

(4)3×

4
9
÷
3
8

=

4
3
÷
3
8

=

32
9

(5)9×

4
7
+9×
3
7
+9

=9×(

4
7
+
3
7
+1)

=9×2

=18;

(6)

15
22
÷[
1
4
÷(
1
2
-
1
3
)]

=

15
22
÷[
1
4
÷
1
6
]

=

15
22
÷
3
2

=

5
11

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