题目内容
把下列每组中的分数通分,并比较大小:
(1)
和
;
(2)
和
;
(3)
,
,
;
(4)
,
,
(5)
,
,1.
(1)
| 5 |
| 12 |
| 3 |
| 4 |
(2)
| 5 |
| 13 |
| 3 |
| 7 |
(3)
| 3 |
| 4 |
| 1 |
| 2 |
| 7 |
| 10 |
(4)
| 5 |
| 6 |
| 4 |
| 5 |
| 5 |
| 12 |
(5)
| 3 |
| 4 |
| 6 |
| 5 |
考点:约分和通分,分数大小的比较
专题:运算顺序及法则
分析:把异分母分数化成大小和原来相等的同分母分数叫做通分,同分母分数大小比较,分子大的分数就大.由此解答.
解答:
解:(1)
=
,
<
;
(2)
=
,
=
,
<
;
(3)
=
,
=
,
=
,
>
>
;
(4)
=
,
=
,
=
,
>
>
;
(5)
=
,
=
,1=
,
<
<
.
| 3 |
| 4 |
| 9 |
| 12 |
| 5 |
| 12 |
| 9 |
| 12 |
(2)
| 5 |
| 13 |
| 35 |
| 91 |
| 3 |
| 7 |
| 39 |
| 91 |
| 35 |
| 91 |
| 39 |
| 91 |
(3)
| 3 |
| 4 |
| 15 |
| 20 |
| 1 |
| 2 |
| 10 |
| 20 |
| 7 |
| 10 |
| 14 |
| 20 |
| 15 |
| 20 |
| 14 |
| 20 |
| 10 |
| 20 |
(4)
| 5 |
| 6 |
| 50 |
| 60 |
| 4 |
| 5 |
| 48 |
| 60 |
| 5 |
| 12 |
| 25 |
| 60 |
| 50 |
| 60 |
| 48 |
| 60 |
| 25 |
| 60 |
(5)
| 3 |
| 4 |
| 15 |
| 20 |
| 6 |
| 5 |
| 24 |
| 20 |
| 20 |
| 20 |
| 15 |
| 20 |
| 20 |
| 20 |
| 24 |
| 20 |
点评:此题考查的目的是使学生理解通分的意义,掌握通分的方法及分数大小比较的方法.
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