题目内容
(2012?洪山区一模)能简便计算的用简便方法计算.
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(
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分析:(1)(5)依据四则运算计算顺序,先算第二级运算,再算第一级运算,如果只含有同一级运算,按照从左到右顺序计算,有括号先算括号里面的解答,
(2)(3)(4)运用乘法分配律间的,
(6)化
=1-
,
=
-
,
=
-
,
=
-
…
=
-
即可解答.
(2)(3)(4)运用乘法分配律间的,
(6)化
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 6 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 12 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 20 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 90 |
| 1 |
| 9 |
| 1 |
| 10 |
解答:解:(1)
÷
×
,
=
×
,
=1
;
(2)
×
+0.25×
-
,
=0.25×(
+
-1),
=0.25×0,
=0;
(3)(
+
)÷
,
=
×
+
×
,
=1
+1,
=2
;
(4)
×
+
÷
,
=
×(
+
),
=
×
,
=
;
(5)
÷[(
+
)×
],
=
÷[
×
],
=
÷
,
=3;
(6)
+
+
+
+…
,
=1-
+
-
+
-
+
-
…+
-
,
=1-
,
=
.
| 10 |
| 13 |
| 35 |
| 26 |
| 7 |
| 3 |
=
| 4 |
| 7 |
| 7 |
| 3 |
=1
| 1 |
| 3 |
(2)
| 4 |
| 7 |
| 1 |
| 4 |
| 3 |
| 7 |
| 1 |
| 4 |
=0.25×(
| 4 |
| 7 |
| 3 |
| 7 |
=0.25×0,
=0;
(3)(
| 7 |
| 8 |
| 13 |
| 16 |
| 13 |
| 16 |
=
| 7 |
| 8 |
| 16 |
| 13 |
| 13 |
| 16 |
| 16 |
| 13 |
=1
| 1 |
| 13 |
=2
| 1 |
| 13 |
(4)
| 1 |
| 7 |
| 5 |
| 12 |
| 5 |
| 12 |
| 7 |
| 5 |
=
| 5 |
| 12 |
| 1 |
| 7 |
| 5 |
| 7 |
=
| 5 |
| 12 |
| 6 |
| 7 |
=
| 5 |
| 14 |
(5)
| 1 |
| 5 |
| 2 |
| 3 |
| 1 |
| 5 |
| 1 |
| 13 |
=
| 1 |
| 5 |
| 13 |
| 15 |
| 1 |
| 13 |
=
| 1 |
| 5 |
| 1 |
| 15 |
=3;
(6)
| 1 |
| 2 |
| 1 |
| 6 |
| 1 |
| 12 |
| 1 |
| 20 |
| 1 |
| 90 |
=1-
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 9 |
| 1 |
| 10 |
=1-
| 1 |
| 10 |
=
| 9 |
| 10 |
点评:本题考查知识点:(1)依据四则运算顺序正确进行计算,(2)正确运用简便算法解决问题.
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