diff --git a/labs/preamble.tex b/labs/preamble.tex
index 8bdbd3e..33a84e6 100644
--- a/labs/preamble.tex
+++ b/labs/preamble.tex
@@ -218,7 +218,7 @@
 \newcommand{\fix}{\todo[color=red!60,noline,size=\large]{Fix}}
 \newcommand{\comment}[1]{\todo[color=yellow!60,inline,size=\large]{#1}}
 \newcommand{\incomplete}{\todo[color=red!60,inline,size=\large]{Incomplete}}
-
+\newcommand{\complete}{\todo[color=green!60,inline,size=\large]{Complete}}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% misc                                                                      %%
@@ -227,3 +227,10 @@
 % a simpler way of getting a right arrow
 \newcommand{\ra}[0]{$\rightarrow$~}
 
+% a section header and counter for exercises
+\newcounter{ExerciseCounter}
+
+\newcommand{\exercise}[1]{%
+	\stepcounter{ExerciseCounter}%
+	\section{Exercise \arabic{ExerciseCounter}~--~#1}
+}