4.per 5 - 2 per 10 -2 per 4 =

≡ penyelesaian :

[tex] = \frac{4}{5} - \frac{2}{10} - \frac{2}{4} \\ \\ = \frac{4}{5} - \frac{1}{5} - \frac{1}{2} \\ \\ = \frac{8 - 2 - 5}{10} \\ \\ = \frac{1}{10} [/tex]