[tex]a) \: \: \frac{ 1 }{ 2 } + \frac{ 5 }{ 4 } = \frac{7}{4} = 1 \frac{3}{4} [/tex]
[tex]b) \: \: 2- \frac{ 4 }{ 5 } = \frac{10}{5}-\frac{4}{5} =\frac{6}{5} = 1 \frac{1}{5} [/tex]
[tex]c) \: \: 2.5-2 \frac{ 3 }{ 8 } = \frac{5}{2}-\frac{19}{8} = \frac{20}{8}-\frac{19}{8} = \frac{1}{8} [/tex]