let's firstly, convert the decimal amounts to fractions, by using as many zeros at the bottom as there are decimals and lose the dot above, then let's compare each.
[tex]\bf 3.\underline{5}\implies \cfrac{35}{1\underline{0}}\implies \cfrac{7}{2}~\hfill 6.\underline{5}\implies \cfrac{65}{1\underline{0}}\implies \cfrac{13}{2} \\\\\\ 9.\underline{5}\implies \cfrac{95}{1\underline{0}}\implies \cfrac{19}{2} \\\\[-0.35em] \rule{34em}{0.25pt}[/tex]
[tex]\bf 3.5\times 6.5\implies \cfrac{3.5}{6.5}\implies \cfrac{~~\frac{7}{2}~~}{\frac{13}{2}}\implies \cfrac{7}{2}\cdot \cfrac{2}{13}\implies \boxed{\cfrac{7}{13}} \\\\\\ 4\times 9.5\implies \cfrac{4}{9.5}\implies \cfrac{~~\frac{4}{1}~~}{\frac{19}{2}}\implies \cfrac{4}{1}\cdot \cfrac{2}{19}\implies \boxed{\cfrac{8}{19}} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{nope}{\cfrac{7}{13}\ne\cfrac{8}{19}}~\hfill[/tex]
