How to Write a Real Number(ℝ) Symbol in LaTeX?

The real number symbol ℝ is one of the most common notations in mathematics. In LaTeX, this symbol is written with the command \mathbb{R}.

Depending on which package you load, the design of the ℝ symbol can change slightly.

Using mathbb Command

The command mathbb is used for the real number symbol. It works with different font packages, each producing a slightly different look. The table below shows the available options.

amsfonts	`\mathbb{R}` →
amssymb	`\mathbb{R}` →
txfonts	`\mathbb{R}` →
pxfonts	`\mathbb{R}` →

The output is the same for amsfonts and amssymb, while txfonts and pxfonts give slightly different styles.

\documentclass{article}
\usepackage{amsfonts} 
\begin{document}
  \[ a,b\in\mathbb{R} \] 
\end{document}

Output

Real Space (Rⁿ, R²)

The notation \mathbb{R} can be combined with a superscript to show real vector spaces. This is common in linear algebra, physics, and engineering.

\documentclass{article}
\usepackage{amsfonts} 
\begin{document}
 \[ \mathbb{R}^n \]
 \[ \mathbb{R}^2 \] 
\end{document}

Real Part of a Complex Number

A complex number has two components: a real part and an imaginary part. The real part is written with ℜ or Re in LaTeX.

\documentclass{article}
\usepackage{amsfonts} 
\begin{document}
  \[ z=a+ib \]
  \[ \Re(z) = a \]
\end{document}

Output

There are several ways to typeset the real part depending on which package you use.

With the physics package

This version prints Re(z) instead of the default ℜ symbol.

\documentclass{article}
\usepackage{physics}
\begin{document}
  \[ z = a+ib \]
  \[ \Re(z) = a \]
\end{document}

Output

With the amsmath package

Using \operatorname creates an upright operator-style notation.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
  \[ z = a+ib \]
  \[ \operatorname{Re}(z) = a \]
\end{document}

Output

With the amsfonts package

The \mathfrak command can be used to produce a gothic-style symbol.

\documentclass{article}
\usepackage{amsfonts}
\begin{document}
  \[ z = a+ib \]
  \[ \mathfrak{R}(z) = a \]
  \[ \mathfrak{Re}(z) = a \]
\end{document}

Output