0.8 has one decimal.. so... let's make it a fraction first, by using one zero with a one as denominator.
[tex]\bf 0.\underline{8}\implies \cfrac{08}{1\underline{0}}\impliedby \textit{one decimal, one zero, no dot}
\\\\\\
\cfrac{8}{10}\implies \cfrac{4}{5}
\qquad \qquad \qquad
......\cfrac{1}{5}..\cfrac{2}{5}..\cfrac{3}{5}..\boxed{\cfrac{4}{5}}..\cfrac{5}{5}..\cfrac{6}{5}..\cfrac{7}{5}......[/tex]
is between any of those, among many other fractions as well.
