题目内容
计算:(要求写出主要计算过程)
(1)[2
+(5.4-3
)×1
]÷3
(2)[(10.75-4
)×2
]÷[(1.125+
)÷(2.25÷10
)].
(1)[2
| 1 |
| 3 |
| 2 |
| 13 |
| 2 |
| 3 |
| 4 |
| 9 |
(2)[(10.75-4
| 11 |
| 12 |
| 7 |
| 11 |
| 1 |
| 12 |
| 10 |
| 11 |
分析:(1)先算小括号内的,再算周公括号内的乘法,然后算中括号内的加法,最后算括号外的除法;
(2)把小数化为分数,原式变为[(
-
)×
]÷[(
+
)÷(
÷
)],小括号内的同时计算,变为[
×
]÷[
÷
],进一步计算,得出结果.
(2)把小数化为分数,原式变为[(
| 43 |
| 4 |
| 59 |
| 12 |
| 29 |
| 11 |
| 5 |
| 4 |
| 1 |
| 12 |
| 9 |
| 4 |
| 120 |
| 11 |
| 35 |
| 6 |
| 29 |
| 11 |
| 4 |
| 3 |
| 33 |
| 160 |
解答:解:(1)[2
+(5.4-3
)×1
]÷3
,
=[2
+(5
-3
)×1
]÷3
,
=[2
+
×
]÷3
,
=[2
+
]÷3
,
=
×
,
=
;
(2)[(10.75-4
)×2
]÷[(1.125+
)÷(2.25÷10
)],
=[(
-
)×
]÷[(
+
)÷(
÷
)],
=[
×
]÷[
÷(
×
)],
=[
×
]÷[
÷
],
=[
×
]÷[
×
],
=[
×
]÷
,
=
×
×
,
=
.
| 1 |
| 3 |
| 2 |
| 13 |
| 2 |
| 3 |
| 4 |
| 9 |
=[2
| 1 |
| 3 |
| 2 |
| 5 |
| 2 |
| 13 |
| 2 |
| 3 |
| 4 |
| 9 |
=[2
| 1 |
| 3 |
| 146 |
| 65 |
| 5 |
| 3 |
| 4 |
| 9 |
=[2
| 1 |
| 3 |
| 146 |
| 39 |
| 4 |
| 9 |
=
| 247 |
| 39 |
| 9 |
| 31 |
=
| 57 |
| 31 |
(2)[(10.75-4
| 11 |
| 12 |
| 7 |
| 11 |
| 1 |
| 12 |
| 10 |
| 11 |
=[(
| 43 |
| 4 |
| 59 |
| 12 |
| 29 |
| 11 |
| 9 |
| 8 |
| 1 |
| 12 |
| 9 |
| 4 |
| 120 |
| 11 |
=[
| 35 |
| 6 |
| 29 |
| 11 |
| 29 |
| 24 |
| 9 |
| 4 |
| 11 |
| 120 |
=[
| 35 |
| 6 |
| 29 |
| 11 |
| 29 |
| 24 |
| 33 |
| 160 |
=[
| 35 |
| 6 |
| 29 |
| 11 |
| 29 |
| 24 |
| 160 |
| 33 |
=[
| 35 |
| 6 |
| 29 |
| 11 |
| 580 |
| 99 |
=
| 35 |
| 6 |
| 29 |
| 11 |
| 99 |
| 580 |
=
| 21 |
| 8 |
点评:在脱式计算中,特别注意运算顺序和运算法则,对分数、小数、百分数的互化要细心.根据题目情况,灵活处理.
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