a)
[tex]\frac{4}{7} -> \frac{2}{7} -> \frac{3}{7} -> \frac{4}{7} -> \frac{2}{7}[/tex]
b)
[tex]\frac{4}{5} -> \frac{3}{5} -> 1 -> \frac{5}{9} -> \frac{7}{9}[/tex]
