$$\frac{3}{4} = 0,75$$
$$\frac{5}{8} = 0,625$$
$$\frac{7}{4} = 1,75$$
$$\frac{83}{25} = \frac{83 \cdot 4}{25 \cdot 4} = \frac{332}{100} = 3,32$$
$$5\frac{1}{2} = 5,5$$
$$70\frac{3}{75} = 70\frac{1}{25} = 70,04$$
$$4\frac{21}{84} = 4\frac{1}{4} = 4,25$$