## 4 Results  
In total 135 students participated in the study between 2013 and 2020. From this set, 103 students used the older versions of the VRLEs (VRLEs-1, Figure 3), of which 82 used the VRLE-1 dedicated to the TPD exercises (Figure 3a) and 81 the VRLE-1 dedicated to CL studies (Figure 3b). The average scores assigned by the students to each question (Table 1) are summarized in Table 2. Furthermore, as shown in Table 3, 53 students used the later versions of the VRLEs (VRLEs-2), of which all of them used the VRLE-2 dedicated to solve TPD exercises (Figure 4a) but only 32 students used the VRLE-2 system (Figure 4b) dedicated for CL studies. The average scores assigned by the students to each question (Table 1) are shown in Table 3. The results of both Tables 2 and 3 are illustrated in Figure 6 (data corresponding to both VRLE versions of the TPD) and Figure 7 (data corresponding to both VRLE versions of the CL). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Question** & **Number** & **KPI** \\ \hline \multirow{4}{*}{Rate from 1 to 10 the following features of the VRLE (1 the lowest rate and 10 the highest)} & 1 & Motivation felt when using the VRLE \\ \cline{2-3}  & 2 & Interactivity level of the VRLE \\ \cline{2-3}  & 3 & Ease of use of the VRLE \\ \cline{2-3}  & 4 & Usefulness of the didactic tool \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Questions (related to this article) designed on surveys for students. Figure 5: Procedure used to implement the VRLEs in the classroom. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**VRLE-1**} & \multirow{2}{*}{\
\begin{tabular}{c} **Academic** \\ **Year** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Number of** \\ **Students** \\ \end{tabular} } & \multicolumn{2}{c}{**Question 1**} & \multicolumn{2}{c}{**Question 2**} & \multicolumn{2}{c}{**Question 3**} & \multicolumn{2}{c}{**Question 4**} \\ \cline{3-10}  & & & **Mean** & \(\sigma\) & **Mean** & \(\sigma\) & **Mean** & \(\sigma\) & **Mean** & \(\sigma\) \\ \hline
**TPD** & \multirow{2}{*}{2013–2014} & \multirow{2}{*}{22} & 8.6 & 0.50 & 7.5 & 0.96 & 7.1 & 0.75 & 9.7 & 0.48 \\
**CL** & & & **-** & **-** & **-** & **-** & **-** & **-** & **-** & **-** & **-** \\ \hline
**TPD** & \multirow{2}{*}{2014–2015} & \multirow{2}{*}{20} & 8.5 & 0.61 & 7.2 & 0.89 & 7.2 & 0.83 & 9.7 & 0.47 \\
**CL** & & & 7.5 & 0.61 & 9.0 & 0.85 & 9.0 & 0.74 & 9.7 & 0.59 \\ \hline
**TPD** & \multirow{2}{*}{2015–2016} & \multirow{2}{*}{20} & 8.1 & 0.72 & 6.5 & 0.89 & 7.0 & 0.73 & 9.7 & 0.49 \\
**CL** & & & 7.5 & 0.69 & 8.5 & 0.76 & 8.8 & 0.75 & 9.6 & 0.60 \\ \hline
**TPD** & \multirow{2}{*}{2016–2017} & \multirow{2}{*}{20} & 7.5 & 0.87 & 6.2 & 0.77 & 7.1 & 0.79 & 9.7 & 0.47 \\
**CL** & & & 7.3 & 0.73 & 8.2 & 0.82 & 9.1 & 0.65 & 9.8 & 0.44 \\ \hline
**TPD** & \multirow{2}{*}{2017–2018} & \multirow{2}{*}{21} & \multirow{2}{*}{6.9} & \multirow{2}{*}{1.00} & \multirow{2}{*}{7.5} & \multirow{2}{*}{1.03} & \multirow{2}{*}{8.9} & \multirow{2}{*}{0.76} & \multirow{2}{*}{9.7} & \multirow{2}{*}{0.46} \\
**CL** & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mean and standard deviation (\(\sigma\)) of students’ scores from surveys given from 2013 to 2017 to each question of the Table 1 for VRLEs developed formerly (VRLE-1, Figure 3).