题目内容
计算下面各题,怎么简便怎么算.
18÷
|
2-
|
| ||||||||||||||||
(
|
4÷
|
|
分析:(1)按照从左到右的顺序计算;
(2)根据减法的性质简算;
(3)(4)运用乘法分配律简算;
(5)先算除法,再算减法;
(6)先把中括号里面的计算运用乘法分配律简算,再算括号外的除法.
(2)根据减法的性质简算;
(3)(4)运用乘法分配律简算;
(5)先算除法,再算减法;
(6)先把中括号里面的计算运用乘法分配律简算,再算括号外的除法.
解答:解:(1)18÷
×
,
=63×
,
=15;
(2)2-
-
,
=2-(
+
),
=2-1,
=1;
(3)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(4)(
+
-
)×36,
=
×36+
×36-
×36,
=24+6-27,
=30-27,
=3;
(5)4÷
-0.6,
=
-
,
=
;
(6)
÷[(
+
)×15],
=
÷[
×15+
×15],
=
÷[10+3],
=
÷13,
=
.
2 |
7 |
5 |
21 |
=63×
5 |
21 |
=15;
(2)2-
3 |
14 |
11 |
14 |
=2-(
3 |
14 |
11 |
14 |
=2-1,
=1;
(3)
1 |
5 |
4 |
7 |
1 |
5 |
3 |
7 |
=
1 |
5 |
4 |
7 |
3 |
7 |
=
1 |
5 |
=
1 |
5 |
(4)(
2 |
3 |
1 |
6 |
3 |
4 |
=
2 |
3 |
1 |
6 |
3 |
4 |
=24+6-27,
=30-27,
=3;
(5)4÷
8 |
3 |
=
3 |
2 |
3 |
5 |
=
9 |
10 |
(6)
1 |
5 |
2 |
3 |
1 |
5 |
=
1 |
5 |
2 |
3 |
1 |
5 |
=
1 |
5 |
=
1 |
5 |
=
1 |
65 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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