How do I number equations in Typst?

Add a set rule: #set math.equation(numbering: "(1)"). Every block equation is then numbered. Suppress the number for one equation with #set math.equation(numbering: none) inside a scope, or by making it inline.

How do I label and reference an equation in Typst?

Attach a label after the closing dollar with angle brackets, $ ... $ , and reference it with @eq:f. Numbering must be switched on for the reference to render a number.

How do I align equations in Typst?

Put & at the alignment point on each line and separate lines with a single backslash, inside one block equation. Every line then lines up on the & column.

How do I left-align an equation in Typst?

Block equations are centred by default. Wrap the equation in #set align(left) for a scope, or use #show math.equation: set align(left) to left-align every block equation in the document.

How do I make a letter upright as an operator in Typst?

Use op("l") to typeset it as an operator name in upright type with operator spacing, or upright(l) for upright type alone. Single letters are italic by default because they read as variables.

How do I strike out part of an equation in Typst?

Use #strike for a plain strikethrough, or the cancel function from a package for the diagonal cancellation bar used when simplifying an expression.

How to write equations and math in Typst

Math goes between $…$ in Typst. Whitespace decides the form: $x^2$ stays inline, while $ x^2 $ — with spaces inside the dollars — becomes a centred block. Turn on numbering with #set math.equation(numbering: "(1)"), and align multi-line math on &.

Multi-letter names are read as functions or symbols, so write x y for a product and spell pi, alpha, and sum by name.

Inline like $E = m c^2$, or as a block:
$ integral_0^1 x^2 dif x = 1/3 $

$A line with the inline equation E equals m c squared followed by a centred integral of x squared from 0 to 1 equalling one third.$

A complete document you can paste

#set page(paper: "a4", margin: 2.5cm)
#set math.equation(numbering: "(1)")

= Method

The loss is the mean squared error over the batch:

$ cal(L) = 1/N sum_(i=1)^N (y_i - hat(y)_i)^2 $ <eq:loss>

Expanding the square gives

$ (x+1)^2 &= (x+1)(x+1) \
          &= x^2 + 2x + 1 $ <eq:expand>

By @eq:loss and @eq:expand, the gradient is straightforward.

$An A4 page with a numbered mean-squared-error equation (1), a two-line aligned expansion (2), and a sentence referencing both by number.$

Numbering and references

One set rule numbers every block equation. Attach a label with <eq:f> after the closing $, and reference it with @eq:f. To leave a single equation unnumbered, scope a rule around it.

#set math.equation(numbering: "(1)")

$ a^2 + b^2 = c^2 $ <eq:pyth>

#[
  #set math.equation(numbering: none)
  $ "this one has no number" $
]

See @eq:pyth.

$A numbered Pythagorean equation (1), an unnumbered equation below it, and a sentence referencing equation 1.$

Alignment

Inside one block equation, & marks the alignment point and a single \ ends a line. Everything lines up on the & column.

$ f(x) &= (x+1)^2 \
       &= x^2 + 2x + 1 \
       &>= 0 $

$A three-line aligned derivation of (x+1) squared, each line aligned on its relation symbol.$

Block equations are centred by default. To left-align them, set the alignment — for one equation with a scope, or for the whole document with a show rule.

#show math.equation: set align(left)

$ y = m x + b $

$The equation y equals m x plus b set flush left rather than centred.$

Upright names, operators, and text

A single letter is italic because it reads as a variable. op("…") makes it an operator name — upright, with operator spacing — and upright(…) changes only the style. Quoted text inside math is set upright automatically.

$ op("l")(x) = upright(d) x quad "for all" x in RR $

$An equation using an upright operator name and upright d, with the words 'for all' in roman type.$

The full symbol list and function reference are in the Typst math documentation. Looking for a quick reference table instead? See Typst math and science symbols.

In KL studioa syntax slip in a math block surfaces in the diagnostics panel as you type, tied to the line it is on — so a stray & or unmatched $ is caught right there instead of in a wall of compiler output.

Common questions

How do I number equations in Typst?: Add a set rule: #set math.equation(numbering: "(1)"). Every block equation is then numbered. Suppress the number for one equation with #set math.equation(numbering: none) inside a scope, or by making it inline.
How do I label and reference an equation in Typst?: Attach a label after the closing dollar with angle brackets, $ ... $ <eq:f>, and reference it with @eq:f. Numbering must be switched on for the reference to render a number.
How do I align equations in Typst?: Put & at the alignment point on each line and separate lines with a single backslash, inside one block equation. Every line then lines up on the & column.
How do I left-align an equation in Typst?: Block equations are centred by default. Wrap the equation in #set align(left) for a scope, or use #show math.equation: set align(left) to left-align every block equation in the document.
How do I make a letter upright as an operator in Typst?: Use op("l") to typeset it as an operator name in upright type with operator spacing, or upright(l) for upright type alone. Single letters are italic by default because they read as variables.
How do I strike out part of an equation in Typst?: Use #strike for a plain strikethrough, or the cancel function from a package for the diagonal cancellation bar used when simplifying an expression.