\documentclass[12pt]{book}
\usepackage[many]{tcolorbox}
\usepackage[margin=2cm]{geometry}
\usepackage[none]{hyphenat}
\begin{document}
\chapter{Number Theory}
\setcounter{section}{1}
\tcbsidebyside[title= \section{Prime and Composite Numbers},
sidebyside adapt=left,
colback=white,
colframe=blue!50!black,
fonttitle=\bfseries,
lower separated=false,
%drop lifted shadow,
sidebyside align=top seam,
]{%
\Huge\textcolor{blue!50!black}{OBJECTIVES}
}{%
\raggedright
\begin{enumerate}
\item Identify whole numbers greater than one as prime or composite.
\item Factor a whole number into a product of prime numbers.
\item Find the greatest common factor of two or more whole numbers.
\item Find the least common multiple of two or more whole numbers.
\end{enumerate}
}
\end{document}
提前致谢。