\documentclass{standalone}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Schola}
\usepackage{tikz}
\usepackage{adjustbox}
\begin{document}
\adjustbox{scale=2}{%
\begin{tikzpicture}
    [
        level 1/.style={sibling distance=48mm},
        level 2/.style={sibling distance=24mm},
        level 3/.style={sibling distance=12mm},
        level 4/.style={sibling distance=6mm},
    ]
        \node {$1/1$}
            child {
                node {$1/2$}
                child {
                    node {$1/3$} 
                    child {
                        node {$1/4$}
                        child {node {}}
                        child {node {}}
                    }
                    child {
                        node {$4/3$}
                        child {node {}}
                        child {node {}}
                    }
                }
                child {
                    node {$3/2$} 
                    child {
                        node {$3/5$}
                        child {node {}}
                        child {node {}}
                    }
                    child {
                        node {$5/2$}
                        child {node {}}
                        child {node {}}
                    }
                }
            }
            child {
                node {$2/1$}
                child {
                    node {$2/3$} 
                    child {
                        node {$2/5$}
                        child {node {}}
                        child {node {}}
                    }
                    child {
                        node {$5/3$}
                        child {node {}}
                        child {node {}}
                    }
                }
                child {
                    node {$3/1$} 
                    child {
                        node {$3/4$}
                        child {node {}}
                        child {node {}}
                    }
                    child {
                        node {$4/1$}
                        child {node {}}
                        child {node {}}
                    }
                }
            };
    \end{tikzpicture}
}
\end{document}