a)
[tex]5,15-(-3\frac{5}{6})= \frac{515}{100} -(-3\frac{5}{6})=\frac{103}{20} +3\frac{5}{6}=\frac{103}{20}+\frac{23}{6}=\frac{539}{60}=8\frac{59}{60}[/tex]
b)
[tex]-5\frac{4}{5}-3,1= -\frac{29}{5}-\frac{31}{10}=-\frac{89}{10}=-8\frac{9}{10}[/tex]
c)
[tex]-6\frac{4}{7}+4,5= -\frac{46}{7}+\frac{9}{2}=-\frac{29}{14}=-2\frac{1}{14}[/tex]
d)
[tex]-5,6-(-2\frac{3}{8})= -\frac{28}{5}+2\frac{3}{8}=-\frac{28}{5}+\frac{19}{8}=-\frac{129}{40}=-3\frac{9}{40}[/tex]
