$\text{$\dfrac{666}{999}$ = $\dfrac{666 : 333}{999 : 333}$ = $\dfrac{2}{3}$}$

$\text{$\dfrac{4000}{6000}$ = $\dfrac{4000 : 2000}{6000 : 2000}$ = $\dfrac{2}{3}$}$

$\text{$\dfrac{500}{1000}$ = $\dfrac{500 : 500}{1000 : 500}$ = $\dfrac{1}{2}$}$

$\text{$\dfrac{15}{1515}$ = $\dfrac{15 : 15}{1515 : 15}$ = $\dfrac{1}{101}$}$

$\text{$\dfrac{201201}{119119}$ = $\dfrac{201201 : 1001}{119119 : 1001}$ = $\dfrac{201}{119}$}$

$\text{Chúc bạn học tốt nha!}$

`@Lynh`

Đáp án+Giải thích các bước giải:

`b)(666)/(999)`

`=(666:111)/(999:111)`

`=6/3`

`=(6:3)/(3:3)`

`=2/1`

`=2`

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`(4000)/(6000)`

`=(4xx1000)/(6xx1000)`

`=4/6`

`=(4:2)/(6:2)`

`=2/3`

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`(500)/(1000)`

`=(500:500)/(1000:5)`

`=1/2`

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`(15)/(1515)`

`=(15:15)/(1515:15)`

`=1/(101)`

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`(201201)/(119119)`

`=(201)/(119)`