Answer:
[tex]\frac{2}{3}[/tex]
Step-by-step explanation:
12: (1 x 12) (2 x 6) (3 x 4)
18: (1 x 18) (2 x 9) (3 x 6)
Since 6 is the highest each can go, that is what you will use to make the fraction into its lowest term.
[tex]\frac{12}{18} / \frac{6}{6}[/tex]
[tex]\frac{2}{3}[/tex]