题目内容
(2011?广州模拟)
| 计算下面各题,能简算的要简算. (1)2
|
(2)4-
|
(3)
| ||||||||||||||||||||||||
(4)(
|
(5)
|
(6)
|
分析:(1)先去掉括号,再运算;括号前的运算符号是减号,所以去括号时括号内的加法变成减法,减法变成加法;
(2)先计算除法,再根据连续减去两个数等于减去这两个数的和来简算;
(3)先把小数化成分数,把除法变成乘法,再运用乘法分配律简算;
(4)先算小括号里面的减法,再算括号外的乘法,最后算除法;
(5)运用乘法分配律简算;
(6)先算小括号里面的加法,再算中括号里面的乘法,最后算括号外的除法.
(2)先计算除法,再根据连续减去两个数等于减去这两个数的和来简算;
(3)先把小数化成分数,把除法变成乘法,再运用乘法分配律简算;
(4)先算小括号里面的减法,再算括号外的乘法,最后算除法;
(5)运用乘法分配律简算;
(6)先算小括号里面的加法,再算中括号里面的乘法,最后算括号外的除法.
解答:解:(1)2
-(
-
),
=2
-
+
,
=2+
,
=2
;
(2)4-
÷
-
,
=4-
-
,
=4-(
+
),
=4-2,
=2;
(3)
×0.6+
÷
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(4)(
-
)×
÷
,
=
×
÷
,
=
÷
,
=
;
(5)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(6)
÷[(
+
)×
],
=
÷[
×
],
=
÷
,
=3.
| 3 |
| 7 |
| 3 |
| 7 |
| 1 |
| 8 |
=2
| 3 |
| 7 |
| 3 |
| 7 |
| 1 |
| 8 |
=2+
| 1 |
| 8 |
=2
| 1 |
| 8 |
(2)4-
| 9 |
| 10 |
| 6 |
| 5 |
| 5 |
| 4 |
=4-
| 3 |
| 4 |
| 5 |
| 4 |
=4-(
| 3 |
| 4 |
| 5 |
| 4 |
=4-2,
=2;
(3)
| 5 |
| 7 |
| 2 |
| 7 |
| 5 |
| 3 |
=
| 5 |
| 7 |
| 3 |
| 5 |
| 2 |
| 7 |
| 3 |
| 5 |
=
| 3 |
| 5 |
| 5 |
| 7 |
| 2 |
| 7 |
=
| 3 |
| 5 |
=
| 3 |
| 5 |
(4)(
| 1 |
| 2 |
| 1 |
| 3 |
| 3 |
| 4 |
| 1 |
| 4 |
=
| 1 |
| 6 |
| 3 |
| 4 |
| 1 |
| 4 |
=
| 1 |
| 8 |
| 1 |
| 4 |
=
| 1 |
| 2 |
(5)
| 5 |
| 7 |
| 3 |
| 8 |
| 5 |
| 8 |
| 5 |
| 7 |
=
| 5 |
| 7 |
| 3 |
| 8 |
| 5 |
| 8 |
=
| 5 |
| 7 |
=
| 5 |
| 7 |
(6)
| 1 |
| 5 |
| 2 |
| 3 |
| 1 |
| 5 |
| 1 |
| 13 |
=
| 1 |
| 5 |
| 13 |
| 15 |
| 1 |
| 13 |
=
| 1 |
| 5 |
| 1 |
| 15 |
=3.
点评:乘法分配律是常用的简便运算的方法,要熟练掌握,灵活运用.
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