问题 解答题
灵活选择算法脱式计算
(1)
1
5
÷(3-
7
13
-
6
13
)

(2)2011×
2009
2010

(3)125×(8+0.8+0.08)
(4)
7
9
÷
11
5
+
5
9
×
2
11
答案

(1)

1
5
÷(3-
7
13
-
6
13
)

=

1
5
÷[3-(
7
13
+
6
13
)],

=

1
5
÷[3-1],

=

1
5
÷2,

=

1
10

(2)2011×

2009
2010

=(2010+1)×

2009
2010

=2010×

2009
2010
+1×
2009
2010

=2009+

2009
2010

=2009

2009
2010

(3)125×(8+0.8+0.08)

=125×8+125×0.8+125×0.08,

=1000+100+10,

=1110;

(4)

7
9
÷
11
5
+
5
9
×
2
11

=

7
9
×
5
11
+
5
9
×
2
11

=

5
9
×
7
11
+
5
9
×
2
11

=

5
9
×(
7
11
+
2
11
),

=

5
9
×
9
11

=

5
11

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