[Tex/LaTex] Number sets symbols in LaTeX

Question

Does anybody know how I can get exactly that symbol for the set of real numbers in LaTeX?

Additional image:

In this picture you have the symbol for the set of integers, real numbers and complex numbers. I think this must be a package.

Answer 1

An exact font for the symbols does not exist, because the symbols are composed from letters. The image clearly shows, that especially the Z- and C-symbols are poor man's versions of the symbol. All the three symbols are generated by two shifted letters:

\documentclass{article}
\newcommand*{\CC}{%
  \textsf{C\kern-1ex C}%
}
\newcommand*{\RR}{%
  \textsf{I\kern-.3ex R}%
}
\newcommand*{\ZZ}{%
  \textsf{Z\kern-1ex Z}%
}
\begin{document}
\textbf{a)} nad \ZZ,
\textbf{b)} nad \RR,
\textbf{c)} nad \CC
\end{document}

Alternatives for comparison

Package amssymb

\documentclass{article}
\usepackage{amssymb}
\begin{document}
\textbf{a)} nad $\mathbb{Z}$,
\textbf{b)} nad $\mathbb{R}$,
\textbf{c)} nad $\mathbb{C}$
\end{document}

Package fourier

\documentclass{article}
\usepackage{fourier}
\begin{document}
\textbf{a)} nad $\mathbb{Z}$,
\textbf{b)} nad $\mathbb{R}$,
\textbf{c)} nad $\mathbb{C}$
\end{document}

Package dsfont

\documentclass{article}
\usepackage{dsfont}
\begin{document}
\textbf{a)} nad $\mathds{Z}$,
\textbf{b)} nad $\mathds{R}$,
\textbf{c)} nad $\mathds{C}$
\end{document}

Sans serif version of dsfont

\documentclass{article}
\usepackage[sans]{dsfont}
\begin{document}
\textbf{a)} nad $\mathds{Z}$,
\textbf{b)} nad $\mathds{R}$,
\textbf{c)} nad $\mathds{C}$
\end{document}

Font "Segoe UI Symbol" (LuaTeX/XeTeX)

\documentclass{article}
\usepackage{fontspec}
\newfontface\SymbolFont{Segoe UI Symbol}
\begin{document}
\textbf{a)} nad {\SymbolFont\symbol{"2124}},
\textbf{b)} nad {\SymbolFont\symbol{"211D}},
\textbf{c)} nad {\SymbolFont\symbol{"2102}}
\end{document}

Font "FreeSans" (LuaTeX/XeTeX)

\documentclass{article}
\usepackage{fontspec}
\newfontfamily\SymbolFont{FreeSans}
\begin{document}
\textbf{a)} nad {\SymbolFont\symbol{"2124}},
\textbf{b)} nad {\SymbolFont\symbol{"211D}},
\textbf{c)} nad {\SymbolFont\symbol{"2102}}
\end{document}