Hugo starts by adding 9 five times, like this: $$9+9+9+9+9$$However, this takes time. Instead, he uses the times table for a quicker method.
As \(\begin{aligned}\textcolor{colordef}{5}\times \textcolor{colorprop}{0}&=\textcolor{olive}{0}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{1}&=\textcolor{olive}{5}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{2}&=\textcolor{olive}{10}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{3}&=\textcolor{olive}{15}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{4}&=\textcolor{olive}{20}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{5}&=\textcolor{olive}{25}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{6}&=\textcolor{olive}{30}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{7}&=\textcolor{olive}{35}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{8}&=\textcolor{olive}{40}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{9}&=\textcolor{olive}{45}\\\textcolor{colordef}{5}\times \textcolor{colorprop}{10}&=\textcolor{olive}{50}\end{aligned}\), \(\textcolor{colordef}{5}\times \textcolor{colorprop}{9}=\textcolor{olive}{45}\).
So, Hugo will need 45 pencils to fill all the boxes. This example shows why learning the times table is helpful.