\documentclass [12pt]{article}
\usepackage {multicol}

\begin{document}
Efect\'{u}a las siguientes operaciones:
\begin{enumerate}
\begin{multicols}{4}
\item
\[
\frac{14}{9} - \frac{7}{32} =
\]
\item
\[
\frac{8}{13} - \frac{26}{48} =
\]
\item
\[
\frac{119}{52} - \frac{28}{65} =
\]
\item
\[
\frac{18}{5} - \frac{13}{38} =
\]
\item
\[
\frac{21}{33} + \frac{19}{86} - \frac{5}{7} =
\]
\item
\[
\frac{6}{5} - \frac{3}{15} - \frac{2}{10} =
\]
\item
\[
\frac{30}{20} - \frac{13}{15} - \frac{1}{21} =
\]
\item
\[
\frac{68}{5} + \frac{6}{204} - \frac{61}{14} =
\]
\item
\[
\frac{18}{90} + \frac{15}{21} - \frac{14}{17} =
\]
\item
\[
\frac{15}{6} - \frac{8}{25} =
\]
\item
\[
\frac{6}{9} - \frac{15}{36} =
\]
\item
\[
\frac{110}{63} - \frac{29}{59} =
\]
\item
\[
\frac{20}{5} - \frac{15}{61} =
\]
\item
\[
\frac{16}{35} + \frac{85}{86} - \frac{9}{7} =
\]
\item
\[
\frac{6}{5} - \frac{6}{12} - \frac{12}{20} =
\]
\item
\[
\frac{20}{15} - \frac{10}{15} - \frac{2}{32} =
\]
\item
\[
\frac{14}{6} + \frac{15}{12} - \frac{12}{52} =
\]
\item
\[
\frac{25}{92} + \frac{16}{26} - \frac{9}{17} =
\]
\item
\[
\frac{12}{6} - \frac{9}{36} =
\]
\item
\[
\frac{9}{12} - \frac{32}{45} =
\]
\item
\[
\frac{112}{56} - \frac{10}{60} =
\]
\item
\[
\frac{12}{14} - \frac{25}{40} =
\]
\item
\[
\frac{14}{45} + \frac{15}{75} - \frac{6}{8} =
\]
\item
\[
\frac{10}{6} - \frac{8}{16} - \frac{3}{6} =
\]
\item
\[
\frac{25}{15} - \frac{12}{18} - \frac{6}{40} =
\]
\item
\[
\frac{47}{6} + \frac{3}{4} - \frac{6}{12} =
\]
\item
\[
\frac{16}{3} + \frac{12}{25} - \frac{3}{12} =
\]
\item
\[
\frac{18}{6} - \frac{8}{15} =
\]
\item
\[
\frac{6}{4} - \frac{14}{57} =
\]
\item
\[
\frac{120}{25} - \frac{25}{68} =
\]
\item
\[
\frac{14}{7} - \frac{12}{21} =
\]
\item
\[
\frac{23}{37} + \frac{11}{54} - \frac{3}{8} =
\]
\item
\[
\frac{12}{9} - \frac{2}{12} - \frac{4}{11} =
\]
\item
\[
\frac{8}{6} - \frac{11}{14} - \frac{3}{19} =
\]
\item
\[
\frac{38}{9} + \frac{12}{24} - \frac{6}{18} =
\]
\item
\[
\frac{17}{65} + \frac{14}{26} =
\]
\item
\[
\frac{18}{6} - \frac{16}{6} =
\]
\item
\[
\frac{45}{40} - \frac{16}{40} =
\]
\item
\[
\frac{120}{10} - \frac{20}{64} =
\]
\item
\[
\frac{12}{6} - \frac{18}{30} =
\]
\item
\[
\frac{25}{35} + \frac{5}{8} - \frac{1}{7} =
\]
\item
\[
\frac{8}{6} - \frac{3}{8} - \frac{4}{13} =
\]
\item
\[
\frac{28}{25} - \frac{6}{13} - \frac{11}{26} =
\]
\item
\[
\frac{55}{5} + \frac{8}{24} - \frac{42}{84} =
\]
\item
\[
\frac{6}{5} + \frac{16}{26} - \frac{15}{29} =
\]
\item
\[
\frac{18}{6} - \frac{5}{9} =
\]
\item
\[
\frac{10}{15} - \frac{18}{40} =
\]
\item
\[
\frac{31}{38} - \frac{15}{30} =
\]
\item
\[
\frac{14}{14} - \frac{25}{52} =
\]
\item
\[
\frac{6}{3} + \frac{20}{50} - \frac{3}{4} =
\]
\item
\[
\frac{6}{5} - \frac{6}{10} - \frac{1}{2} =
\]
\item
\[
\frac{12}{10} - \frac{10}{20} - \frac{6}{15} =
\]
\item
\[
\frac{52}{55} + \frac{8}{24} - \frac{32}{54} =
\]
\item
\[
\frac{40}{38} + \frac{15}{5} - \frac{8}{17} =
\]
\end{multicols}
\end{enumerate}





\end{document}