\documentclass[11pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{fourier}
\usepackage[scaled=0.875]{helvet} 
\renewcommand{\ttdefault}{lmtt} 
\usepackage{amsmath,amssymb,makeidx}
\usepackage[normalem]{ulem}
\usepackage{fancybox,graphics,graphicx}
\usepackage{graphicx}
\usepackage{tabularx}
\usepackage{pifont}
\usepackage{ulem}
\usepackage{dcolumn}
\usepackage{textcomp}
\usepackage{ifthen}
\usepackage{diagbox}
\usepackage{scratch}
\usepackage{enumitem}
\usepackage{tabularx}
\usepackage{multirow}
\usepackage{lscape}

%Tapuscrit : leonidasse DIMANCHE
\usepackage{pstricks,pst-plot,pst-text,pst-tree,pstricks-add}
\usepackage[left=2cm, right=2cm, top=2cm, bottom=2cm]{geometry}
\usepackage{tikz}
\usetikzlibrary{patterns}
\newcommand{\euro}{\eurologo{}}
\newtheorem{exo}{\blue\textbf{{Exercice}}}
\newcommand{\vect}[1]{\overrightarrow{\,\mathstrut#1\,}}
\newcommand{\R}{\mathbb{R}}
\newcommand{\N}{\mathbb{N}}
\newcommand{\D}{\mathbb{D}}
\newcommand{\Z}{\mathbb{Z}}
\newcommand{\Q}{\mathbb{Q}}
\newcommand{\C}{\mathbb{C}}
\newcommand{\DATE}{12222}
\newcommand{\DM}{DEVOIR MAISON N°\np{25}}
\newcommand{\CLASSE}{Classe: $5^{ème}$}
%\newcommand{\repere}{##BB#MATMEAG1}
\renewcommand{\theenumi}{\textbf{\arabic{enumi}}}
\renewcommand{\labelenumi}{\textbf{\theenumi.}}
\renewcommand{\theenumii}{\textbf{\alph{enumii}}}
\renewcommand{\labelenumii}{\textbf{\theenumii.}}
\def\Oij{$\left(\text{O}~;~\vect{\imath},~\vect{\jmath}\right)$}
\def\Oijk{$\left(\text{O}~;~\vect{\imath},~\vect{\jmath},~\vect{k}\right)$}
\def\Ouv{$\left(\text{O}~;~\vect{u},~\vect{v}\right)$}
\usepackage{fancyhdr}
\usepackage{hyperref}
%\usepackage{scratch3}

\usepackage[frenchb]{babel}
\usepackage[np]{numprint}

\begin{document}
\setlength\parindent{0mm}
\rhead{\textbf{\DATE}}
\lhead{\small \CLASSE}
%\rfoot{\small \DATE}
%\lfoot{\small \repere}

\pagestyle{fancy}

\begin{center}
 \textbf{\textsc{\DM }} 
\end{center}

\exo : \\

\exo :

\end{document}
