a) [tex]\frac{1}{3} - \frac{2}{3} =\frac{-1}{3}[/tex]
b) [tex]\frac{-1}{3} +\frac{-2}{3} =\frac{-3}{3} =-1[/tex]
c) [tex]\frac{-1}{3} - \frac{-2}{3} = \frac{-1}{3} +\frac{2}{3} =\frac{1}{3}[/tex]
d) [tex]\frac{1}{5} + \frac{-3}{15} = \frac{3}{15} -\frac{3}{15} = 0[/tex]
e) [tex]\frac{-1}{2} + \frac{-3}{8} = \frac{-4}{8} +\frac{-3}{8} =\frac{-7}{8}[/tex]
f) [tex]\frac{-1}{5} - \frac{-7}{10} = \frac{-2}{10} +\frac{7}{10} =\frac{5}{10} =\frac{1}{2}[/tex]
