题目内容
计算(能简算的要简算).
|
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|
(
|
分析:(1)先算小括号里面的减法,再把除法变成乘法,运用乘法结合律简算;
(2)运用乘法分配律简算;
(3)先算小括号里面的加法,再算括号外的乘法;
(4)先运用乘法分配律简算,再运用加法结合律简算.
(2)运用乘法分配律简算;
(3)先算小括号里面的加法,再算括号外的乘法;
(4)先运用乘法分配律简算,再运用加法结合律简算.
解答:解:(1)
÷(1-
)×
,
=
÷
×
,
=
×(4×
),
=
×3,
=
;
(2)
×
+20%×
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(3)
÷(
+
),
=
÷
,
=
;
(4)(
+
)×
+
,
=
×
+
×
+
,
=
+
+
,
=
+(
+
),
=
+1,
=1
.
| 5 |
| 6 |
| 3 |
| 4 |
| 3 |
| 4 |
=
| 5 |
| 6 |
| 1 |
| 4 |
| 3 |
| 4 |
=
| 5 |
| 6 |
| 3 |
| 4 |
=
| 5 |
| 6 |
=
| 5 |
| 2 |
(2)
| 1 |
| 5 |
| 6 |
| 11 |
| 5 |
| 11 |
=
| 1 |
| 5 |
| 6 |
| 11 |
| 1 |
| 5 |
| 5 |
| 11 |
=
| 1 |
| 5 |
| 6 |
| 11 |
| 5 |
| 11 |
=
| 1 |
| 5 |
=
| 1 |
| 5 |
(3)
| 9 |
| 16 |
| 3 |
| 8 |
| 1 |
| 16 |
=
| 9 |
| 16 |
| 7 |
| 16 |
=
| 9 |
| 7 |
(4)(
| 5 |
| 6 |
| 16 |
| 17 |
| 1 |
| 8 |
| 15 |
| 17 |
=
| 5 |
| 6 |
| 1 |
| 8 |
| 16 |
| 17 |
| 1 |
| 8 |
| 15 |
| 17 |
=
| 5 |
| 48 |
| 2 |
| 17 |
| 15 |
| 17 |
=
| 5 |
| 48 |
| 2 |
| 17 |
| 15 |
| 17 |
=
| 5 |
| 48 |
=1
| 5 |
| 48 |
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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