diff --git a/tex/homework.cls b/tex/homework.cls
index 082d0b5..57056f6 100644
--- a/tex/homework.cls
+++ b/tex/homework.cls
@@ -1,6 +1,7 @@
 \ProvidesClass{homework}
 \LoadClass[fontsize=10pt]{scrartcl}
 
+\RequirePackage{tex-macros}
 \RequirePackage[T1]{fontenc}
 \RequirePackage{textcomp}
 \RequirePackage{stmaryrd}
@@ -35,19 +36,6 @@
 \RequirePackage[framemethod=TikZ]{mdframed}
 \mdfsetup{skipabove=1em, skipbelow=0em, innertopmargin=5pt, innerbottommargin=6pt}
 
-
-\let\sidesum\sum
-\let\sidelim\lim
-\renewcommand\sum{\sidesum\limits}
-\renewcommand\lim{\sidelim\limits}
-\newcommand{\problem}[1]{\subsection*{#1.}}
-\newcommand{\pbl}[1]{\subsection*{#1.}}
-\newcommand{\N}{\ensuremath{\mathbb{N}}}
-\newcommand{\Z}{\ensuremath{\mathbb{Z}}}
-\newcommand{\R}{\ensuremath{\mathbb{R}}}
-\newcommand{\Q}{\ensuremath{\mathbb{Q}}}
-\newcommand\C{\ensuremath{\mathbb{C}}}
-
 \geometry{top=20mm,bottom=20mm}