题目内容
(2013?华亭县模拟)脱式计算(能简算的要简算)
3÷
|
99×
|
2
| ||||||||||||||||
|
[(7
|
分析:(1)先算除法,再算减法,最后算加法;
(2)根据与乘法分配律进行计算;
(3)先算乘法,再根据加法结合律进行计算;
(4)根据乘法分配律进行计算;
(5)根据乘法分配律先算小括号里面的,再算中括号里面的除法,再算括号外面的除法.
(2)根据与乘法分配律进行计算;
(3)先算乘法,再根据加法结合律进行计算;
(4)根据乘法分配律进行计算;
(5)根据乘法分配律先算小括号里面的,再算中括号里面的除法,再算括号外面的除法.
解答:解:
(1)3÷
-
÷3+3
,
=4-
+3
,
=3
+3
,
=7
;
(2)99×
,
=(98+1)×
,
=98×
+1×
,
=87+
,
=87
,
(3)2
+1
×
+
,
=2
+
+
,
=2
+(
+
),
=2
+1,
=3
;
(4)
×5.3+5.7×
-0.625,
=
×5.3+5.7×
-
,
=(5.3+5.7-1)×
,
=10×
,
=
;
(5)[(7
×
+2
÷1
)÷
]÷
,
=[(7
×
+2
×
)÷
]÷
,
=[(7
+2
)×
÷
]÷
,
=[10×
÷
]÷
,
=[6÷
]÷
,
=18÷
,
=54.
(1)3÷
| 3 |
| 4 |
| 3 |
| 4 |
| 3 |
| 4 |
=4-
| 1 |
| 4 |
| 3 |
| 4 |
=3
| 3 |
| 4 |
| 3 |
| 4 |
=7
| 1 |
| 2 |
(2)99×
| 87 |
| 98 |
=(98+1)×
| 87 |
| 98 |
=98×
| 87 |
| 98 |
| 87 |
| 98 |
=87+
| 87 |
| 98 |
=87
| 87 |
| 98 |
(3)2
| 1 |
| 7 |
| 1 |
| 8 |
| 5 |
| 9 |
| 3 |
| 8 |
=2
| 1 |
| 7 |
| 5 |
| 8 |
| 3 |
| 8 |
=2
| 1 |
| 7 |
| 5 |
| 8 |
| 3 |
| 8 |
=2
| 1 |
| 7 |
=3
| 1 |
| 7 |
(4)
| 5 |
| 8 |
| 5 |
| 8 |
=
| 5 |
| 8 |
| 5 |
| 8 |
| 5 |
| 8 |
=(5.3+5.7-1)×
| 5 |
| 8 |
=10×
| 5 |
| 8 |
=
| 25 |
| 4 |
(5)[(7
| 3 |
| 5 |
| 3 |
| 5 |
| 2 |
| 5 |
| 2 |
| 3 |
| 1 |
| 3 |
| 1 |
| 3 |
=[(7
| 3 |
| 5 |
| 3 |
| 5 |
| 2 |
| 5 |
| 3 |
| 5 |
| 1 |
| 3 |
| 1 |
| 3 |
=[(7
| 3 |
| 5 |
| 2 |
| 5 |
| 3 |
| 5 |
| 1 |
| 3 |
| 1 |
| 3 |
=[10×
| 3 |
| 5 |
| 1 |
| 3 |
| 1 |
| 3 |
=[6÷
| 1 |
| 3 |
| 1 |
| 3 |
=18÷
| 1 |
| 3 |
=54.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
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