we know that
A mixed number is a number consisting of a whole number and a proper fraction.
so
[tex]1.8=1+0.8\\\\ =1+\frac{8}{10}\\\\ =1+\frac{4}{5}\\ \\=1\frac{4}{5}[/tex]
therefore
the answer is
[tex]1\frac{4}{5}[/tex]
