问题 解答题
[2.25+(3
3
5
-1.21×
5
11
)]÷40%            
1
1
2
+2
1
6
+3
1
12
+4
1
20
+…+10
1
110

(5.4×1
1
3
+6
3
5
÷0.75)×125.5
(1+
2
3
+
3
4
+
4
5
)×( 
2
3
+
3
4
+
4
5
+
5
6
)-( 1+
2
3
+
3
4
+
4
5
+
5
6
)×( 
2
3
+
3
4
+
4
5
答案

(1)[2.25+(3

3
5
-1.21×
5
11
)]÷40%,

=[2.25+(3.6-0.55)]÷0.4,

=[2.25+3.05]÷0.4,

=5.3÷0.4,

=13.25;

(2)1

1
2
+2
1
6
+3
1
12
+4
1
20
+…+10
1
110

=(1+

1
2
)+(2+
1
6
)+(3+
1
12
)+(4+
1
20
)+…+(10+
1
110
),

=(1+2+3+4+…+10)+(

1
2
+
1
6
+
1
12
+
1
20
+…+
1
110

=(1+10)×10÷2+(

1
1×2
+
1
2×3
+
1
3×4
+
1
4×5
+…+
1
10×11
),

=11×10÷2+(1-

1
2
+
1
2
-
1
3
+
1
3
-
1
4
+
1
4
-
1
5
+…+
1
10
-
1
11
),

=55+(1-

1
11
),

=55+

10
11

=55

10
11

(3)(5.4×1

1
3
+6
3
5
÷0.75)×125.5

=(5.4×

4
3
+6.6÷0.75)×125.5

=(7.2+8.8)×125.5,

=16×125.5,

=2008;

(4)(1+

2
3
+
3
4
+
4
5
)×(
2
3
+
3
4
+
4
5
+
5
6
)-(1+
2
3
+
3
4
+
4
5
+
5
6
)×(
2
3
+
3
4
+
4
5
),

=(1+

2
3
+
3
4
+
4
5
)×(
2
3
+
3
4
+
4
5
+
5
6
)-[1×(
2
3
+
3
4
+
4
5
)+(
2
3
+
3
4
+
4
5
+
5
6
)×(
2
3
+
3
4
+
4
5
)],

=(1+

2
3
+
3
4
+
4
5
)×(
2
3
+
3
4
+
4
5
+
5
6
)-(
2
3
+
3
4
+
4
5
)-(
2
3
+
3
4
+
4
5
+
5
6
)×(
2
3
+
3
4
+
4
5
),

=(

2
3
+
3
4
+
4
5
+
5
6
)×[(1+
2
3
+
3
4
+
4
5
)-(
2
3
+
3
4
+
4
5
)]-(
2
3
+
3
4
+
4
5
),

=(

2
3
+
3
4
+
4
5
+
5
6
)-(
2
3
+
3
4
+
4
5
),

=

5
6

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