[tex]A=\left \{ x\:|\:x\:\in\:\mathbb{N} \:si\:x\:\in\:D_{12}\right \}[/tex]
[tex]D_{12}=\left \{ \pm1,\pm2,\pm3,\pm4,\pm6,\pm12 \right \}[/tex]
[tex]x \: \in \: \mathbb{N} = > x \: \in \: \left \{ 1,2,3,4,6,12 \right \}[/tex]
[tex] = > A=\left \{ 1,2,3,4,6,12 \right \}[/tex]
