\begin{tikzpicture}
    \draw[very thick,red]   (0,0) -- (2.5,0) node [midway, below] {$\gamma_1$};
    \draw[very thick,green](2.5,0) -- (5,0) node [midway, below] {$\gamma_2$};
    \draw[very thick,blue] (5,0) -- (10,0) node [midway, below] {$\gamma_3$};

    \draw[thick] (0,0.2)   -- (  0,-0.2) node[label=below:$0$] {};
    \draw[thick] (2.5,0.2) -- (2.5,-0.2) node[label=below:$\nicefrac{1}{4}$] {};
    \draw[thick] (5.0,0.2) -- (5.0,-0.2) node[label=below:$\nicefrac{1}{2}$] {};
    \draw[thick] (10,0.2)  -- ( 10,-0.2) node[label=below:$1$] {};
\end{tikzpicture}
