diff --git a/logique-programmable/exercices/ctd2.tex b/logique-programmable/exercices/ctd2.tex
index 438d0cf..b55777e 100644
--- a/logique-programmable/exercices/ctd2.tex
+++ b/logique-programmable/exercices/ctd2.tex
@@ -31,6 +31,32 @@
 
     \item
 
+    \item
+
+    \item \begin{itemize}
+            \item Rappeler les équations logiques d'un demi-additionneur 2 bits.
+                Le décrire en VHDL\@.
+                \begin{align*}
+                    \texttt{s} &= \texttt{a} \oplus \texttt{b} \\
+                    \texttt{cout} &= \texttt{a} \cdot \texttt{b}
+                \end{align*}
+                \begin{lstlisting}[gobble=20]
+                    s = a xor b;
+                    cout = a and b;
+                \end{lstlisting}
+
+            \item Rappeler les équations logiques d'un additionneur complet.
+                Le décrire en VHDL à partir de la description d'un demi-additionneur.
+                \begin{align*}
+                    \texttt{full\_s} &= (\texttt{full\_a} \oplus \texttt{full\_b}) \oplus \texttt{full\_cin} \\
+                    \texttt{full\_cout} &= \texttt{full\_a} \cdot \texttt{full\_b} + \texttt{full\_cin} \cdot (\texttt{full\_a} \oplus \texttt{full\_b})
+                \end{align*}
+                \begin{lstlisting}[gobble=20]
+                    full_s = (full_a xor full_b) xor full_cin;
+                    full_cout = full_a and full_b or full_cin and (full_a xor full_b);
+                \end{lstlisting}
+        \end{itemize}
+
 \end{enumerate}
 
 \end{document}