How to write number sets R Z Q N with Latex ?

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

$\mathbf{R}$ is the set of real numbers.

So we use the \ mathbf command. Which give:

$\mathbf{R}$ is the set of reals.

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:


and \mathbb command

$\mathbb{R}$ is the set of real numbers.

$\mathbb{R}$ is the set of real numbers.

An another example:

$$\mathbb{N} \subset \mathbb{Z} \subset \mathbb{D} \subset \mathbb{Q} \subset \mathbb{R} \subset \mathbb{C}$$
\[\mathbb{N} \subset \mathbb{Z} \subset \mathbb{D} \subset \mathbb{Q} \subset \mathbb{R} \subset \mathbb{C}\]