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# Latex rational numbers

How to write the set of rational numbers in Latex !

## Set of rational numbers

In old books, classic mathematical number sets are marked in bold as follows


$\mathbf{Q}$ is the set of rational numbers.


So we use the \ mathbf command. Which give:

$\mathbf{Q}$ is the set of rational numbers.

You will have noticed that in recent books, we use a font that is based on double bars, this notation is actually derived from the writing of classic sets on the blackboard: indeed, on the blackboard we do not fill these sets, or it would take a ton of chalk !!! In Latex, we use the amsfonts package
In the preamble we have:


\usepackage{amsfonts}


and \mathbb command


$\mathbb{Q}$ is the set of rational numbers.


$\mathbb{Q}$ is the set of rational numbers.