Răspuns:
12. a) [tex]\frac{17}{60}[/tex] b) [tex]\frac{29}{60}[/tex]
16. a) [tex]\frac{3}{15},\frac {5}{15}[/tex] b) [tex]\frac{3}{81},\frac{9}{81} ,\frac{27}{81}[/tex] c) [tex]\frac{2}{28},\frac{4}{28},\frac{7}{28},\frac{14}{28}[/tex] d) [tex]\frac{3}{45},\frac{5}{45},\frac{9}{45},\frac{15}{45}[/tex]