Verified Answer :

You mean simplify? 

You can't simplify it anymore because the numerator is an even number and the denominator odd..

But,

\(\frac{4}{5}\) = 0.8

And equivalent fraction:

Multiply 2 from the numerator and denominator

\(\frac{4~multiply~by~2}{5~multiply~by~2} = \frac{8}{10}\)

You can not decompose 4/5 because it is not possible. If you try to decompose 4/5 then you would get a negative answer or an error.