题目内容
(1)〔14
-(3.78-3.78÷1
)×1〕÷3.2
(2)4
×1
+2
÷
+29×
+5.7×2.
| 1 |
| 3 |
| 2 |
| 7 |
(2)4
| 4 |
| 5 |
| 11 |
| 24 |
| 2 |
| 7 |
| 16 |
| 21 |
| 1 |
| 2 |
分析:(1)先算小括号内的,运用乘法分配律计算,再算中括号内的,最后算括号外的;
(2)把带分数化为假分数,把除法化为乘法,约分计算即可.
(2)把带分数化为假分数,把除法化为乘法,约分计算即可.
解答:解:(1)[14
-(3.78-3.78÷1
)×1]÷3.2,
=[14
-(3.78-3.78×
)×1]÷3.2,
=[14
-3.78×(1-
)×1]÷3.2,
=[14
-3.78×
×1]÷3.2,
=[14
-0.84]÷3.2,
=[14
-
]÷
,
=
×
,
=
;
(2)4
×1
+2
÷
+29×
+5.7×2,
=
×
+
×
+29×
+11.4,
=7+3+14.5+11.4,
=35.9.
| 1 |
| 3 |
| 2 |
| 7 |
=[14
| 1 |
| 3 |
| 7 |
| 9 |
=[14
| 1 |
| 3 |
| 7 |
| 9 |
=[14
| 1 |
| 3 |
| 2 |
| 9 |
=[14
| 1 |
| 3 |
=[14
| 1 |
| 3 |
| 21 |
| 25 |
| 17 |
| 5 |
=
| 334 |
| 25 |
| 5 |
| 17 |
=
| 334 |
| 85 |
(2)4
| 4 |
| 5 |
| 11 |
| 24 |
| 2 |
| 7 |
| 16 |
| 21 |
| 1 |
| 2 |
=
| 24 |
| 5 |
| 35 |
| 24 |
| 16 |
| 7 |
| 21 |
| 16 |
| 1 |
| 2 |
=7+3+14.5+11.4,
=35.9.
点评:此题考查了分数的四则混合运算,注意运算顺序和运算法则.
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