题目内容
计算各题,能简便运算的写出主要过程.
36×(
|
1-
|
| ||||||||||||||||||
[1-(
|
(
|
|
分析:(1)(5)(6)运用乘法分配律简算;
(2)先算除法,再算减法;
(3)先把除法变成乘法,再运用乘法分配律简算;
(4)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的除法.
(2)先算除法,再算减法;
(3)先把除法变成乘法,再运用乘法分配律简算;
(4)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的除法.
解答:解:(1)36×(
+
+
),
=36×
+36×
+36×
,
=9+6+4,
=19;
(2)1-
÷
,
=1-
,
=
;
(3)
×
+
÷1
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(4)[1-(
+
)]÷
,
=[1-
]÷
,
=
÷
,
=
;
(5)(
-
)×36,
=36×
-
×36,
=21-10,
=11;
(6)
×
+
×
,
=
×(
+
),
=
×1,
=
.
| 1 |
| 4 |
| 1 |
| 6 |
| 1 |
| 9 |
=36×
| 1 |
| 4 |
| 1 |
| 6 |
| 1 |
| 9 |
=9+6+4,
=19;
(2)1-
| 7 |
| 9 |
| 7 |
| 8 |
=1-
| 8 |
| 9 |
=
| 1 |
| 9 |
(3)
| 3 |
| 5 |
| 2 |
| 3 |
| 2 |
| 5 |
| 1 |
| 2 |
=
| 3 |
| 5 |
| 2 |
| 3 |
| 2 |
| 5 |
| 2 |
| 3 |
=(
| 3 |
| 5 |
| 2 |
| 5 |
| 2 |
| 3 |
=1×
| 2 |
| 3 |
=
| 2 |
| 3 |
(4)[1-(
| 1 |
| 4 |
| 3 |
| 8 |
| 1 |
| 4 |
=[1-
| 5 |
| 8 |
| 1 |
| 4 |
=
| 3 |
| 8 |
| 1 |
| 4 |
=
| 3 |
| 2 |
(5)(
| 7 |
| 12 |
| 5 |
| 18 |
=36×
| 7 |
| 12 |
| 5 |
| 18 |
=21-10,
=11;
(6)
| 7 |
| 18 |
| 1 |
| 4 |
| 3 |
| 4 |
| 7 |
| 18 |
=
| 7 |
| 18 |
| 1 |
| 4 |
| 3 |
| 4 |
=
| 7 |
| 18 |
=
| 7 |
| 18 |
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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