问题 解答题
(1)2011×
2009
2010
+1004×
1004
1005

(2)(
1
2
x-9)×
1
5
=x-9
(3)
1
2
+
5
6
+
11
12
+
19
20
+…+
109
110

(4)
573+697×572
573×697-124
+
363636
727272

(5)2009÷2009
2009
2010
+2009
1
2011

(6)
2
1×7
+
2
7×13
+
2
13×19
+…+
2
145×151
答案

(1)2011×

2009
2010
+1004×
1004
1005

=(2010+1)×

2009
2010
+(1005-1)×
1004
1005

=2010×

2009
2010
+
2009
2010
+1005×
1004
1005
-
1004
1005

=2009+

2009
2010
+1004-
2008
2010

=3013+

1
2010

=3013

1
2010

(2)(

1
2
x-9)×
1
5
=x-9,

1
2
x-9)×
1
5
×5=(x-9)×5,

1
2
x-9=5x-45,

1
2
x-9+9=5x-45+9,

1
2
x=5x-36,

1
2
x-
1
2
x=5x-36-
1
2
x,

4

1
2
x-36=0,

4

1
2
x-36+36=0+36,

9
2
x=36,

9
2
2
9
=36×
2
9

x=8;

(3)

1
2
+
5
6
+
11
12
+
19
20
+…+
109
110

=1-

1
2
+1-
1
6
+1-
1
12
+1-
1
20
+…+1-
1
110

=1+1+…+1-(

1
2
+
1
6
+
1
12
+
1
20
+…+
1
110
),

=10-(1-

1
2
+
1
2
-
1
3
+
1
3
-
1
4
+…+
1
10
-
1
11
),

=10-(1-

1
11
),

=10-1+

1
11

=9

1
11

(4)

573+697×572
573×697-124
+
363636
727272

=

573+697×(573-1)
573×697-124
+
36×10101
72×10101

=

573×697-124
573×697-124
+
1
2

=1+

1
2

=1

1
2

(5)2009÷2009

2009
2010
+2009
1
2011

=2009÷

2010×2009+2009
2010
+2009+
1
2011

=2009×

2010
2009×2011
+2009+
1
2011

=

2010
2011
+
1
2011
+2009,

=1+2009,

=2010;

(6)

2
1×7
+
2
7×13
+
2
13×19
+…+
2
145×151

=

1
3
×(
6
1×7
+
6
7×13
+
6
13×19
+…+
6
145×151

=

1
3
×(1-
1
7
+
1
7
-
1
13
+
1
13
-
1
19
+…
1
145
-
1
151

=

1
3
×(1-
1
151

=

1
3
×
150
151

=

50
151

单项选择题
单项选择题