Phân số \(\dfrac{4}{9}\)  bằng mấy phân số trong các phân số sau: \(\dfrac{{48}}{{108}};\dfrac{{80}}{{180}};\dfrac{{60}}{{130}};\dfrac{{135}}{{270}}\)?

Ư$(6) = \left\{ {{\rm{1,2,3,6}}} \right\}$; Ư${\rm{(20) = }}\left\{ {{\rm{1,2,4,5,10,20}}} \right\}$; ƯC${\rm{(6,20) = }}\left\{ {{\rm{1,2}}} \right\}$                    

Ư$(6) = \left\{ {{\rm{1,2,3,6}}} \right\}$; Ư${\rm{(20) = }}\left\{ {{\rm{1,2,4,5,20}}} \right\}$; ƯC${\rm{(6,20) = }}\left\{ {{\rm{1,2}}} \right\}$                  

Ư$(6) = \left\{ {{\rm{1,2,3}}} \right\}$; Ư${\rm{(20) = }}\left\{ {{\rm{1,2,4,5,10,20}}} \right\}$; ƯC${\rm{(6,20) = }}\left\{ {{\rm{1,2}}} \right\}$            

Ư$(6) = \left\{ {{\rm{1,2,4,6}}} \right\}$; Ư${\rm{(20) = }}\left\{ {{\rm{1,2,4,20}}} \right\}$; ƯC${\rm{(6,20) = }}\left\{ {{\rm{1,2,4}}} \right\}$

$18$                    

$3$                  

$15$            

$5$

ƯCLN$\left( {a,b} \right) = 3.7$                    

ƯCLN$\left( {a,b} \right) = {3^2}{.7^2}$                  

ƯCLN$\left( {a,b} \right) = {2^4}.5$            

ƯCLN$\left( {a,b} \right) = {2^4}{.3^2}.5.7$

$C = \{ $toán, văn, thể dục$\} $

$C = \{ $toán, văn$\} $

$C = \{ $toán, văn, thể dục, ca nhạc$\} $

$C = \{ $toán, thể dục, giáo dục công dân$\} $

$4$                    

$2$                    

$3$                    

$6$                    

$15$                    

$10$                    

$20$                    

$18$                    

\(x \in \left\{ {1;2;4;5;8;10;20} \right\}\)    

\(x \in \left\{ {2;5;10;20;40} \right\}\)                                 

\(x \in \left\{ {1;2;5;10;20;40} \right\}\)           

\(x \in \left\{ {2;5;10;20} \right\}\)