答案1
\documentclass{beamer}
\newcommand{\numcirc}[1]{%
% \usebeamerfont*{item projected}%
\large
\usebeamercolor[bg]{item projected}%
\begin{pgfpicture}{-1ex}{0ex}{1ex}{2ex}
\pgfpathcircle{\pgfpoint{0pt}{.75ex}}{1.2ex}
\pgfusepath{fill}
\pgftext[base]{\color{fg}#1}
\end{pgfpicture}%
\usebeamerfont*{frametitle}%
}
\begin{document}
\begin{frame}
\frametitle{\numcirc{5} test}
\end{frame}
\end{document}