题目内容

(1)200-199+198-197+196 …+2-1
(2)2012×20132013-2013×20122012
(3)1.25×98+12
1
2
×
1
10
+1
1
4

(4)
1
2007
+
2
2007
+
3
2007
+…+
2006
2007

(5)0.35÷0.125÷64÷0.5÷0.25
(6)
1
2
+
5
6
-
7
12
+
9
20
-
11
30
+
13
42
-
15
56
分析:(1)两个1组,分组计算即可;
(2)将2012×20132013-2013×20122012变形为2012×2013×10001-2013×2012×10001,即可求解;
(3)根据乘法分配律简便计算;
(4)根据同分母分数的计算法则和高斯求和公式计算;
(5)先化为分数,除法变为乘法,再约分计算即可;
(6)先拆分,再抵消法计算即可求解.
解答:解:(1)200-199+198-197+196 …+2-1,
=(200-199)+(198-197)+(196 …+(2-1),
=1×100,
=100;

(2)2012×20132013-2013×20122012,
=2012×2013×10001-2013×2012×10001,
=0;

(3)1.25×98+12
1
2
×
1
10
+1
1
4

=1.25×98+1.25+1.25,
=1.25×(98+1+1),
=1.25×100,
=125;

(4)
1
2007
+
2
2007
+
3
2007
+…+
2006
2007

=
1+2+…+2006
2007

=
(1+2006)×2006÷2
2007

=1003;

(5)0.35÷0.125÷64÷0.5÷0.25,
=
7
20
×8×
1
64
×2×4,
=
7
20


(6)
1
2
+
5
6
-
7
12
+
9
20
-
11
30
+
13
42
-
15
56

=1-
1
2
+
1
2
+
1
3
-
1
3
-
1
4
+
1
4
+
1
5
-
1
5
-
1
6
+
1
6
+
1
7
-
1
7
-
1
8

=1-
1
8

=
7
8
点评:考查了四则混合运算中的巧算,注意灵活运用运算律简便计算.
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