题目内容
(2013?湖南)(1)
+0.37=
(2)2
÷[3
-(3.4-2
)]
(3)(
+
+
)×24
(4)
+
+
+…+
+1
(5)
+
+
+…+
(6)
×34.5-
×3.5
(7)
×37
(8)27×
(9)(1+
+
)×(
+
=
)-(1+
+
+
)×(
+
)
(10)(1-
)×(1-
)×(1-
)×…×(1-
)
3 |
8 |
0.745
0.745
(2)2
2 |
9 |
1 |
6 |
2 |
3 |
(3)(
1 |
3 |
1 |
4 |
1 |
8 |
(4)
1 |
2015 |
3 |
2015 |
5 |
2015 |
2013 |
2015 |
(5)
1 |
3×4 |
1 |
4×5 |
1 |
5×6 |
1 |
17×18 |
(6)
1 |
8 |
3 |
8 |
(7)
44 |
55 |
(8)27×
15 |
26 |
(9)(1+
1 |
2 |
1 |
3 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
2 |
1 |
3 |
(10)(1-
1 |
3 |
1 |
4 |
1 |
5 |
1 |
50 |
分析:(1)先把分数变成小数再计算;
(2)先算小括号里面的减法,再算中括号里面的减法,最后算括号外的除法,注意把小数化成分数再计算;
(3)运用乘法分配律简算;
(4)根据同分母分数的加法的计算方法,分母不变,分子相加,把分子看成一个首项是1,末项是2015,等差是2的等差数列,再根据等差数列的求和公式,求出分子的和,进而求解;
(5)
=
-
,
=
-
…
=
-
,由此化简求解;
(6)先运用积不变的规律,把
×3.5变成
×10.5,再运用乘法分配律简算;
(7)先把分数化简,再计算;
(8)先把27分解成26+1,再运用乘法分配律简算;
(9)令
+
=a,然后运用乘法分配律化简,再相减即可求解;
(10)先求出小括号里面的差,再约分求解即可.
(2)先算小括号里面的减法,再算中括号里面的减法,最后算括号外的除法,注意把小数化成分数再计算;
(3)运用乘法分配律简算;
(4)根据同分母分数的加法的计算方法,分母不变,分子相加,把分子看成一个首项是1,末项是2015,等差是2的等差数列,再根据等差数列的求和公式,求出分子的和,进而求解;
(5)
1 |
3×4 |
1 |
3 |
. |
14 |
1 |
4×5 |
1 |
4 |
1 |
5 |
1 |
17×18 |
1 |
17 |
1 |
18 |
(6)先运用积不变的规律,把
3 |
8 |
1 |
8 |
(7)先把分数化简,再计算;
(8)先把27分解成26+1,再运用乘法分配律简算;
(9)令
1 |
2 |
1 |
3 |
(10)先求出小括号里面的差,再约分求解即可.
解答:解:(1)
+0.37,
=0.375+0.37,
=0.745;
(2)2
÷[3
-(3.4-2
)],
=2
÷[3
-
],
=2
÷
.
=
;
(3)(
+
+
)×24,
=
×24+
×24+
×24,
=8+6+3,
=17;
(4)
+
+
+…+
+1,
=
,
=
,
=
;
(5)
+
+
+…+
,
=
-
+
-
+
-
+…+
-
,
=
-
,
=
;
(6)
×34.5-
×3.5,
=
×34.5-(
÷3)×(3.5×3),
=
×34.5-
×10.5,
=
×(34.5-10.5),
=
×24,
=3;
(7)
×37,
=
×37,
=
;
(8)27×
,
=(26+1)×
,
=26×
+1×
,
=15+
,
=15
;
(9)令
+
=a,那么:
(1+
+
)×(
+
+
)-(1+
+
+
)×(
+
),
=(1+a)×(a+
)-(1+
+a)×a,
=(a+a2+
a+
)-(a+
a+a2),
=a+a2+
a+
-a-
a-a2,
=(a-a)+(a2-a2)+(
a-
a)+
,
=0+0+0+
,
=
;
(10)(1-
)×(1-
)×(1-
)×…×(1-
),
=
×
×
×…
×
,
=
,
=
.
3 |
8 |
=0.375+0.37,
=0.745;
(2)2
2 |
9 |
1 |
6 |
2 |
3 |
=2
2 |
9 |
1 |
6 |
11 |
15 |
=2
2 |
9 |
73 |
30 |
=
200 |
219 |
(3)(
1 |
3 |
1 |
4 |
1 |
8 |
=
1 |
3 |
1 |
4 |
1 |
8 |
=8+6+3,
=17;
(4)
1 |
2015 |
3 |
2015 |
5 |
2015 |
2013 |
2015 |
=
1+3+5+…+2015 |
2015 |
=
(1+2015)×1008÷2 |
2015 |
=
1016064 |
2015 |
(5)
1 |
3×4 |
1 |
4×5 |
1 |
5×6 |
1 |
17×18 |
=
1 |
3 |
1 |
4 |
1 |
4 |
1 |
5 |
1 |
5 |
1 |
6 |
1 |
17 |
1 |
18 |
=
1 |
3 |
1 |
18 |
=
5 |
18 |
(6)
1 |
8 |
3 |
8 |
=
1 |
8 |
3 |
8 |
=
1 |
8 |
1 |
8 |
=
1 |
8 |
=
1 |
8 |
=3;
(7)
44 |
55 |
=
4 |
5 |
=
148 |
5 |
(8)27×
15 |
26 |
=(26+1)×
15 |
26 |
=26×
15 |
26 |
15 |
26 |
=15+
15 |
26 |
=15
15 |
26 |
(9)令
1 |
2 |
1 |
3 |
(1+
1 |
2 |
1 |
3 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
2 |
1 |
3 |
=(1+a)×(a+
1 |
4 |
1 |
4 |
=(a+a2+
1 |
4 |
1 |
4 |
1 |
4 |
=a+a2+
1 |
4 |
1 |
4 |
1 |
4 |
=(a-a)+(a2-a2)+(
1 |
4 |
1 |
4 |
1 |
4 |
=0+0+0+
1 |
4 |
=
1 |
4 |
(10)(1-
1 |
3 |
1 |
4 |
1 |
5 |
1 |
50 |
=
2 |
3 |
3 |
4 |
4 |
5 |
48 |
49 |
49 |
50 |
=
2 |
50 |
=
1 |
25 |
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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