diff --git a/2nd/01_Proportion_et_fractions/1_exercises_tech.tex b/2nd/01_Proportion_et_fractions/1_exercises_tech.tex
new file mode 100644
index 0000000..1b37ba2
--- /dev/null
+++ b/2nd/01_Proportion_et_fractions/1_exercises_tech.tex
@@ -0,0 +1,64 @@
+\begin{exercise}[subtitle={Multiplication de fractions}, step={3}, origin={Création}, topics={ Proportion et fractions }, tags={ Statistiques, Fractions }, mode={\searchMode}]
+    Faire les calculs suivants
+    \begin{multicols}{4}
+        \begin{enumerate}[label={\Alph*=}]
+            \item $\dfrac{- 6}{3} + \dfrac{- 7}{3}$
+            \item $\dfrac{- 10}{5} + \dfrac{6}{5}$
+
+            \item $\dfrac{7}{10} + \dfrac{3}{90}$
+            \item $\dfrac{10}{81} + \dfrac{5}{9}$
+
+            \item $\dfrac{7}{9} + \dfrac{3}{10}$
+            \item $\dfrac{8}{5} + \dfrac{3}{7}$
+
+            \item $\dfrac{1}{a} + \dfrac{1}{2a}$
+            \item $\dfrac{3}{5a} + \dfrac{1}{4a}$
+        \end{enumerate}
+    \end{multicols}
+
+\end{exercise}
+
+\begin{solution}
+    \begin{enumerate}[label={\Alph*=}]
+        \item $\dfrac{- 6}{3} + \dfrac{- 7}{3}=\dfrac{- 6 - 7}{3}=\dfrac{- 13}{3} = \dfrac{- 13}{3}$
+        \item $\dfrac{- 10}{5} + \dfrac{6}{5}=\dfrac{- 10 + 6}{5}=\dfrac{- 4}{5} = \dfrac{- 4}{5}$
+        \item $\dfrac{7}{10} + \dfrac{3}{90}=\dfrac{7 \times 9}{10 \times 9} + \dfrac{3}{90}=\dfrac{63}{90} + \dfrac{3}{90}=\dfrac{63 + 3}{90}=\dfrac{66}{90} = \dfrac{11}{15}$
+        \item $\dfrac{10}{81} + \dfrac{5}{9}=\dfrac{10}{81} + \dfrac{5 \times 9}{9 \times 9}=\dfrac{10}{81} + \dfrac{45}{81}=\dfrac{10 + 45}{81}=\dfrac{55}{81} = \dfrac{55}{81}$
+        \item $\dfrac{7}{9} + \dfrac{3}{10}=\dfrac{7 \times 10}{9 \times 10} + \dfrac{3 \times 9}{10 \times 9}=\dfrac{70}{90} + \dfrac{27}{90}=\dfrac{70 + 27}{90}=\dfrac{97}{90} = \dfrac{97}{90}$
+        \item $\dfrac{- 6}{3} + \dfrac{- 7}{3}=\dfrac{- 6 - 7}{3}=\dfrac{- 13}{3} = \dfrac{- 13}{3}$
+        \item $\dfrac{1}{a} + \dfrac{1}{2a} = \dfrac{2}{2a} + \dfrac{1}{2a} = \dfrac{2+1}{2a} = \dfrac{3}{2a}$
+        \item $\dfrac{3}{5a} + \dfrac{1}{4a} = \dfrac{12}{20a} + \dfrac{5}{20a} = \dfrac{12+5}{2a} = \dfrac{17}{2a}$
+    \end{enumerate}
+\end{solution}
+
+\begin{exercise}[subtitle={Multiplication de fractions}, step={3}, origin={Création}, topics={ Proportion et fractions }, tags={ Statistiques, Fractions }, mode={\searchMode}]
+    Faire les calculs suivants
+    \begin{multicols}{4}
+        \begin{enumerate}[label={\Alph*=}]
+            \item $\dfrac{7}{8} \times \dfrac{- 10}{8}$
+            \item $B = \dfrac{3}{10} \times \dfrac{7}{10}$
+
+            \item $\dfrac{3}{4} \times \dfrac{9}{12}$
+            \item $\dfrac{2}{30} \times \dfrac{4}{10}$
+
+            \item $\dfrac{9}{3} \times \dfrac{9}{7}$
+            \item $\dfrac{5}{4} \times \dfrac{3}{7}$
+
+            \item $\dfrac{1}{a} * \dfrac{1}{2a}$
+            \item $\dfrac{3}{5a} * \dfrac{1}{4a}$
+        \end{enumerate}
+    \end{multicols}
+\end{exercise}
+
+\begin{solution}
+    \begin{enumerate}[label={\Alph*=}]
+        \item $\dfrac{7}{8} \times \dfrac{- 10}{8}=\dfrac{7(- 10)}{8 \times 8}=\dfrac{- 70}{64} = \dfrac{- 35}{32}$
+        \item $\dfrac{3}{10} \times \dfrac{7}{10}=\dfrac{3 \times 7}{10 \times 10}=\dfrac{21}{100} = \dfrac{21}{100}$
+        \item $\dfrac{3}{4} \times \dfrac{9}{12}=\dfrac{3 \times 9}{4 \times 12}=\dfrac{27}{48} = \dfrac{9}{16}$
+        \item $\dfrac{2}{30} \times \dfrac{4}{10}=\dfrac{2 \times 4}{30 \times 10}=\dfrac{8}{300} = \dfrac{2}{75}$
+        \item $\dfrac{9}{3} \times \dfrac{9}{7}=\dfrac{9 \times 9}{3 \times 7}=\dfrac{81}{21} = \dfrac{27}{7}$
+        \item $\dfrac{7}{8} \times \dfrac{- 10}{8}=\dfrac{7(- 10)}{8 \times 8}=\dfrac{- 70}{64} = \dfrac{- 35}{32}$
+        \item $\dfrac{1}{a} \times \dfrac{1}{2a} = \dfrac{1\times 1}{a\times 2a} = \dfrac{1}{2a^2}$
+        \item $\dfrac{3}{5a} \times \dfrac{1}{4a} = \dfrac{3\times 1}{5a\times 4a} = \dfrac{3}{20a^2}$
+    \end{enumerate}
+\end{solution}
diff --git a/2nd/01_Proportion_et_fractions/all_exercises.pdf b/2nd/01_Proportion_et_fractions/all_exercises.pdf
index 9fe4f56..c4da229 100644
Binary files a/2nd/01_Proportion_et_fractions/all_exercises.pdf and b/2nd/01_Proportion_et_fractions/all_exercises.pdf differ
diff --git a/2nd/01_Proportion_et_fractions/all_exercises.tex b/2nd/01_Proportion_et_fractions/all_exercises.tex
index 5044892..1cc2b68 100644
--- a/2nd/01_Proportion_et_fractions/all_exercises.tex
+++ b/2nd/01_Proportion_et_fractions/all_exercises.tex
@@ -22,5 +22,6 @@
 \maketitle
 
 \input{exercises.tex}
+\input{1_exercises_tech.tex}
 
 \end{document}
diff --git a/2nd/01_Proportion_et_fractions/bopytex_config.py b/2nd/01_Proportion_et_fractions/bopytex_config.py
new file mode 100644
index 0000000..599b6b5
--- /dev/null
+++ b/2nd/01_Proportion_et_fractions/bopytex_config.py
@@ -0,0 +1,12 @@
+# bopytex_config.py
+from mapytex.calculus.random import expression as random_expression
+from mapytex import render
+import random
+
+random.seed(0)  # Controlling the seed allows to make subject reproductible
+
+render.set_render("tex")
+
+direct_access = {
+    "random_expression": random_expression,
+}
diff --git a/2nd/01_Proportion_et_fractions/exercises.tex b/2nd/01_Proportion_et_fractions/exercises.tex
index 814ce17..96216e7 100644
--- a/2nd/01_Proportion_et_fractions/exercises.tex
+++ b/2nd/01_Proportion_et_fractions/exercises.tex
@@ -43,16 +43,17 @@
 \end{exercise}
 
 \begin{solution}
+        \def\arraystretch{2}
     \begin{enumerate}
-        \item $\frac{120}{150} = \frac{4}{5} = 0.8 = 80\%$
-        \item $\frac{5}{22} \approx  0.22 = 22\%$
+        \item $\dfrac{120}{150} = \dfrac{4}{5} = 0.8 = 80\%$
+        \item $\dfrac{5}{22} \approx  0.22 = 22\%$
         \item
 
             \begin{tabular}{|p{4cm}|*{4}{c|}}
                     \hline
                     Camping & Les flots bleu & Cascade magique & Le tronc dégarni & La vallée plate\\
                     \hline
-                    Proportion en fraction & $\frac{0}{35}$ & $\frac{10}{15}$ & $\frac{40}{75}$ & $\frac{100}{200}$ \\
+                    Proportion en fraction & $\dfrac{0}{35}$ & $\dfrac{10}{15}$ & $\dfrac{40}{75}$ & $\dfrac{100}{200}$ \\
                     \hline
                     Proportion en décimal & 0 & 0.66 & 0.53 & 0.5 \\
                     \hline
@@ -60,6 +61,7 @@
                     \hline
                 \end{tabular}
     \end{enumerate}
+        \def\arraystretch{1.5}
 \end{solution}
 
 
@@ -106,29 +108,31 @@
 \end{exercise}
 
 \begin{solution}
+        \def\arraystretch{2}
         \begin{tabular}{|*{4}{c|}}
             \hline
             Proportion & Fraction irréductible & Effectifs associés & Valeur décimale \\
             \hline
-            10\% & $\frac{1}{10}$ & 10 pour 100, c'est comme 1 pour 10 & 0.1\\
+            10\% & $\dfrac{1}{10}$ & 10 pour 100, c'est comme 1 pour 10 & 0.1\\
             \hline
-            20\% & $\frac{1}{5}$ & 20 pour 100, c'est comme 1 pour 5 & 0.2\\
+            20\% & $\dfrac{1}{5}$ & 20 pour 100, c'est comme 1 pour 5 & 0.2\\
             \hline
-            25\% & $\frac{1}{4}$ & 25 pour 100, c'est comme 1 pour 4 & 0.25\\
+            25\% & $\dfrac{1}{4}$ & 25 pour 100, c'est comme 1 pour 4 & 0.25\\
             \hline
-            33.3\% & $\frac{333}{1000}$ & 33.3 pour 100, c'est comme 333 pour 1000 & 0.333\\
+            33.3\% & $\dfrac{333}{1000}$ & 33.3 pour 100, c'est comme 333 pour 1000 & 0.333\\
             \hline
-            50\% & $\frac{1}{2}$ & 50 pour 100, c'est comme 1 pour 2 &  0.5 \\
+            50\% & $\dfrac{1}{2}$ & 50 pour 100, c'est comme 1 pour 2 &  0.5 \\
             \hline
-            60\% & $\frac{3}{5}$ & 60 pour 100, c'est comme 3 pour 5 & 0.6 \\
+            60\% & $\dfrac{3}{5}$ & 60 pour 100, c'est comme 3 pour 5 & 0.6 \\
             \hline
-            66.7\% & $\frac{667}{1000}$ & 66.7 pour 100, c'est comme 667 pour 1000 & 0.667\\
+            66.7\% & $\dfrac{667}{1000}$ & 66.7 pour 100, c'est comme 667 pour 1000 & 0.667\\
             \hline
-            75\% & $\frac{3}{4}$ & 75 pour 100, c'est comme 3 pour 4 &  0.75 \\
+            75\% & $\dfrac{3}{4}$ & 75 pour 100, c'est comme 3 pour 4 &  0.75 \\
             \hline
             100\% & 1 & 100 pour 100, c'est comme 1 pour 1 & 1\\
             \hline
         \end{tabular}
+        \def\arraystretch{1.5}
 \end{solution}
 
 \begin{exercise}[subtitle={Techniques}, step={1}, origin={MEpC}, topics={ Proportion et fractions }, tags={ Statistiques, Fractions }, mode={\trainMode}]
@@ -148,19 +152,21 @@
 \end{exercise}
 
 \begin{solution}
-    \begin{enumerate}
-        \item $\frac{20}{100} \times 190 = 38$
-        \item $\frac{2}{3} \times 126 = 84$
-        \item $\frac{42}{100} = \frac{31}{50} = 0.42$
-        \item $\frac{78}{100} = \frac{39}{50} = 0.78$
-        \item $\frac{1,5}{5} = \frac{3}{10} = 0.3$
-        \item $\frac{1500}{2300} = \frac{15}{23} \approx 0.65$
-        \item $\frac{30}{100} \times 400 = 120$
-        \item $\frac{0.6}{100} \times \np{2 000 000} = \np{12 000}$
-        \item $ \frac{14}{0.4} = 35$
-        \item $ \frac{150 000}{0.75} = 200 000$
-        \item $ \frac{5\times 30}{0.24} = 625$
-    \end{enumerate}
+    \begin{multicols}{3}
+        \begin{enumerate}
+            \item $\dfrac{20}{100} \times 190 = 38$
+            \item $\dfrac{2}{3} \times 126 = 84$
+            \item $\dfrac{42}{100} = \dfrac{31}{50} = 0.42$
+            \item $\dfrac{78}{100} = \dfrac{39}{50} = 0.78$
+            \item $\dfrac{1,5}{5} = \dfrac{3}{10} = 0.3$
+            \item $\dfrac{1500}{2300} = \dfrac{15}{23} \approx 0.65$
+            \item $\dfrac{30}{100} \times 400 = 120$
+            \item $\dfrac{0.6}{100} \times \np{2 000 000} = \np{12 000}$
+            \item $ \dfrac{14}{0.4} = 35$
+            \item $ \dfrac{150 000}{0.75} = 200 000$
+            \item $ \dfrac{5\times 30}{0.24} = 625$
+        \end{enumerate}
+    \end{multicols}
 \end{solution}
 
 \begin{exercise}[subtitle={Radars}, step={1}, origin={MEpC}, topics={ Proportion et fractions }, tags={ Statistiques, Fractions }, mode={\groupMode}]
@@ -187,11 +193,11 @@
     \begin{enumerate}
         \item Est-il possible de trouver deux nombres entiers distincts $a$ et $b$ tels que:
             \[
-                \frac{1}{a} + \frac{1}{b} = 1
+                \dfrac{1}{a} + \dfrac{1}{b} = 1
             \]
         \item Est-il possible de trouver deux nombres entiers distincts $a$, $b$ et $c$ tels que:
             \[
-                \frac{1}{a} + \frac{1}{b} + \frac{1}{c} = 1
+                \dfrac{1}{a} + \dfrac{1}{b} + \dfrac{1}{c} = 1
             \]
         \item Avec 4 nombres? 5? Et plus?
     \end{enumerate}
@@ -213,11 +219,11 @@
             \end{multicols}
         \item Indiquez sur les disques les fractions correspondantes
             \[
-                \frac{1}{2} \qquad
-                \frac{1}{3} \qquad
-                \frac{1}{4} \qquad
-                \frac{1}{8} \qquad
-                \frac{1}{12} \qquad
+                \dfrac{1}{2} \qquad
+                \dfrac{1}{3} \qquad
+                \dfrac{1}{4} \qquad
+                \dfrac{1}{8} \qquad
+                \dfrac{1}{12} \qquad
             \]
         \item Reconstituez un disque complet à l'aide de 3 portions.
         \item Reconstituez un disque complet à l'aide de 4 portions.
diff --git a/2nd/01_Proportion_et_fractions/solutions.pdf b/2nd/01_Proportion_et_fractions/solutions.pdf
index 5d18ea9..92aa79a 100644
Binary files a/2nd/01_Proportion_et_fractions/solutions.pdf and b/2nd/01_Proportion_et_fractions/solutions.pdf differ
diff --git a/2nd/01_Proportion_et_fractions/solutions.tex b/2nd/01_Proportion_et_fractions/solutions.tex
index 69496cc..5322452 100644
--- a/2nd/01_Proportion_et_fractions/solutions.tex
+++ b/2nd/01_Proportion_et_fractions/solutions.tex
@@ -22,7 +22,6 @@
 \maketitle
 
 \input{exercises.tex}
-%\printcollection{banque}
-%\printsolutions{exercises}
+\input{1_exercises_tech.tex}
 
 \end{document}
diff --git a/2nd/01_Proportion_et_fractions/tpl_exercises_tech.tex b/2nd/01_Proportion_et_fractions/tpl_exercises_tech.tex
new file mode 100644
index 0000000..c1bda40
--- /dev/null
+++ b/2nd/01_Proportion_et_fractions/tpl_exercises_tech.tex
@@ -0,0 +1,76 @@
+\begin{exercise}[subtitle={Multiplication de fractions}, step={3}, origin={Création}, topics={ Proportion et fractions }, tags={ Statistiques, Fractions }, mode={\searchMode}]
+    Faire les calculs suivants
+    \begin{multicols}{4}
+        \begin{enumerate}[label={\Alph*=}]
+            %- set A = random_expression("{a} / {b} + {c} / {b}", ["a!=b", "c!=b", "b > 1"], global_config={"rejected":[-1, 0, 1]})
+            \item $\Var{A}$
+                %- set B = random_expression("{a} / {b} + {c} / {b}", ["a!=b", "c!=b", "b > 1"], global_config={"rejected":[-1, 0, 1]})
+            \item $\Var{B}$
+
+                %- set C = random_expression("{a} / {b} + {c} / {d*b}", ["a!=b", "c!=b", "b > 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{C}$
+                %- set D = random_expression("{a} / {d*b} + {c} / {b}", ["a!=b", "c!=b", "b > 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{D}$
+
+                %- set E = random_expression("{a} / {b} + {c} / {d}", ["a!=b", "c!=b", "gcd(b, d) == 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{E}$
+                %- set F = random_expression("{a} / {b} + {c} / {d}", ["a!=b", "c!=b", "gcd(b, d) == 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{F}$
+
+            \item $\dfrac{1}{a} + \dfrac{1}{2a}$
+            \item $\dfrac{3}{5a} + \dfrac{1}{4a}$
+        \end{enumerate}
+    \end{multicols}
+
+\end{exercise}
+
+\begin{solution}
+    \begin{enumerate}[label={\Alph*=}]
+        \item $\Var{A.simplify().explain() | join('=')} = \Var{A.simplify().simplified}$
+        \item $\Var{B.simplify().explain() | join('=')} = \Var{B.simplify().simplified}$
+        \item $\Var{C.simplify().explain() | join('=')} = \Var{C.simplify().simplified}$
+        \item $\Var{D.simplify().explain() | join('=')} = \Var{D.simplify().simplified}$
+        \item $\Var{E.simplify().explain() | join('=')} = \Var{E.simplify().simplified}$
+        \item $\Var{A.simplify().explain() | join('=')} = \Var{A.simplify().simplified}$
+        \item $\dfrac{1}{a} + \dfrac{1}{2a} = \dfrac{2}{2a} + \dfrac{1}{2a} = \dfrac{2+1}{2a} = \dfrac{3}{2a}$
+        \item $\dfrac{3}{5a} + \dfrac{1}{4a} = \dfrac{12}{20a} + \dfrac{5}{20a} = \dfrac{12+5}{2a} = \dfrac{17}{2a}$
+    \end{enumerate}
+\end{solution}
+
+\begin{exercise}[subtitle={Multiplication de fractions}, step={3}, origin={Création}, topics={ Proportion et fractions }, tags={ Statistiques, Fractions }, mode={\searchMode}]
+    Faire les calculs suivants
+    \begin{multicols}{4}
+        \begin{enumerate}[label={\Alph*=}]
+            %- set A = random_expression("{a} / {b} * {c} / {b}", ["a!=b", "c!=b", "b > 1"], global_config={"rejected":[-1, 0, 1]})
+            \item $\Var{A}$
+                %- set B = random_expression("{a} / {b} * {c} / {b}", ["a!=b", "c!=b", "b > 1"], global_config={"rejected":[-1, 0, 1]})
+            \item $B = \Var{B}$
+
+                %- set C = random_expression("{a} / {b} * {c} / {d*b}", ["a!=b", "c!=b", "b > 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{C}$
+                %- set D = random_expression("{a} / {d*b} * {c} / {b}", ["a!=b", "c!=b", "b > 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{D}$
+
+                %- set E = random_expression("{a} / {b} * {c} / {d}", ["a!=b", "c!=b", "gcd(b, d) == 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{E}$
+                %- set F = random_expression("{a} / {b} * {c} / {d}", ["a!=b", "c!=b", "gcd(b, d) == 1"], global_config={"min_max":(1, 10)})
+            \item $\Var{F}$
+
+            \item $\dfrac{1}{a} * \dfrac{1}{2a}$
+            \item $\dfrac{3}{5a} * \dfrac{1}{4a}$
+        \end{enumerate}
+    \end{multicols}
+\end{exercise}
+
+\begin{solution}
+    \begin{enumerate}[label={\Alph*=}]
+        \item $\Var{A.simplify().explain() | join('=')} = \Var{A.simplify().simplified}$
+        \item $\Var{B.simplify().explain() | join('=')} = \Var{B.simplify().simplified}$
+        \item $\Var{C.simplify().explain() | join('=')} = \Var{C.simplify().simplified}$
+        \item $\Var{D.simplify().explain() | join('=')} = \Var{D.simplify().simplified}$
+        \item $\Var{E.simplify().explain() | join('=')} = \Var{E.simplify().simplified}$
+        \item $\Var{A.simplify().explain() | join('=')} = \Var{A.simplify().simplified}$
+        \item $\dfrac{1}{a} \times \dfrac{1}{2a} = \dfrac{1\times 1}{a\times 2a} = \dfrac{1}{2a^2}$
+        \item $\dfrac{3}{5a} \times \dfrac{1}{4a} = \dfrac{3\times 1}{5a\times 4a} = \dfrac{3}{20a^2}$
+    \end{enumerate}
+\end{solution}