# Variants
Alternate typefaces within formulas.
These functions are distinct from the [`text`] function because math fonts
contain multiple variants of each letter.
## Functions
### `serif`
Serif (roman) font style in math.
This is already the default.
### `sans`
Sans-serif font style in math.
### `frak`
Fraktur font style in math.
### `mono`
Monospace font style in math.
### `bb`
Blackboard bold (double-struck) font style in math.
For uppercase latin letters, blackboard bold is additionally available
through [symbols]($category/symbols/sym) of the form `NN` and `RR`.
### `cal`
Calligraphic font style in math.