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diff --git a/crates/typst-library/src/math/frac.rs b/crates/typst-library/src/math/frac.rs
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+++ b/crates/typst-library/src/math/frac.rs
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+use typst_syntax::Spanned;
+
+use crate::diag::bail;
+use crate::foundations::{elem, Content, Value};
+use crate::math::Mathy;
+
+/// A mathematical fraction.
+///
+/// # Example
+/// ```example
+/// $ 1/2 < (x+1)/2 $
+/// $ ((x+1)) / 2 = frac(a, b) $
+/// ```
+///
+/// # Syntax
+/// This function also has dedicated syntax: Use a slash to turn neighbouring
+/// expressions into a fraction. Multiple atoms can be grouped into a single
+/// expression using round grouping parenthesis. Such parentheses are removed
+/// from the output, but you can nest multiple to force them.
+#[elem(title = "Fraction", Mathy)]
+pub struct FracElem {
+    /// The fraction's numerator.
+    #[required]
+    pub num: Content,
+
+    /// The fraction's denominator.
+    #[required]
+    pub denom: Content,
+}
+
+/// A binomial expression.
+///
+/// # Example
+/// ```example
+/// $ binom(n, k) $
+/// $ binom(n, k_1, k_2, k_3, ..., k_m) $
+/// ```
+#[elem(title = "Binomial", Mathy)]
+pub struct BinomElem {
+    /// The binomial's upper index.
+    #[required]
+    pub upper: Content,
+
+    /// The binomial's lower index.
+    #[required]
+    #[variadic]
+    #[parse(
+        let values = args.all::<Spanned<Value>>()?;
+        if values.is_empty() {
+            // Prevents one element binomials
+            bail!(args.span, "missing argument: lower");
+        }
+        values.into_iter().map(|spanned| spanned.v.display()).collect()
+    )]
+    pub lower: Vec<Content>,
+}