8 là ước chung của

$x \in $Ư$\left( a \right)$ và $x \in B(b)$                

$x \subset Ư(a)$và $x \subset Ư(b)$

$x \in $Ư\(\left( a \right)\) và  $x \in $Ư\(\left( b \right)\)    

$x \notin Ư(a)$ và $x \notin Ư(b)$

$6$                 

$30$                           

$12$                         

$18$

${\rm{\{ 1;3\} }}$                      

${\rm{\{ 0;3\} }}$                         

${\rm{\{ 1;5\} }}$                              

${\rm{\{ 1;3;9\} }}$

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

36

6

12

24

20

160

30

50