问题 解答题
计算下面各题,怎样简便就怎样算
5
9
×(
9
5
+18)
4
5
-
4
5
÷4
1
2
×
3
5
+
2
5
×
1
2
1
7
×
5
13
+
8
13
÷7
19-19×
99
100
7
8
-
4
9
×
3
8
答案

(1)

5
9
×(
9
5
+18),

=

5
9
×
9
5
+
5
9
×18,

=1+10,

=11;

(2)4÷

4
5
-
4
5
÷4,

=5-

1
5

=4

4
5

(3)

1
2
×
3
5
+
2
5
×
1
2

=

1
2
×(
3
5
+
2
5
),

=

1
2
×1,

=

1
2

(4)

1
7
×
5
13
+
8
13
÷7,

=

1
7
×
5
13
+
8
13
×
1
7

=

1
7
×(
5
13
+
8
13
),

=

1
7
×1,

=

1
7

(5)19-19×

99
100

=19×(1-

99
100
),

=19×

1
100

=

19
100

(6)

7
8
-
4
9
×
3
8

=

7
8
-
4
24

=

17
24

单项选择题
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