$$A=\frac{5}{4}+\frac{13}{4}; B=\frac{23}{12}-\frac{20}{12}; c=\frac{1}{7}+\frac{5}{21}; D=-\frac{3}{5}$$
$A = \frac{9}{2} = 4\frac{1}{2} = 4.5$
$B=\frac{1}{4}=0.25$
$c=\frac{8}{21}\approx 0.380952381$
$D=-\frac{3}{5}=-0.6$
