diff --git a/src/formatting.typ b/src/formatting.typ
index 3f16b28..db2e34b 100644
--- a/src/formatting.typ
+++ b/src/formatting.typ
@@ -162,7 +162,7 @@
     frac: it.frac,
     group: it.group,
     digits: it.digits,
-    decimal-separator: it.decimal-separator,
+    decimal-separator: [#it.decimal-separator],
   ))
 
   return sequence((
diff --git a/tests/num/decimal-separator/.gitignore b/tests/num/decimal-separator/.gitignore
new file mode 100644
index 0000000..2e4c5d8
--- /dev/null
+++ b/tests/num/decimal-separator/.gitignore
@@ -0,0 +1,5 @@
+# generated by tytanic, do not edit
+
+/diff/
+/out/
+/ref/
diff --git a/tests/num/decimal-separator/ref.typ b/tests/num/decimal-separator/ref.typ
new file mode 100644
index 0000000..cb453f3
--- /dev/null
+++ b/tests/num/decimal-separator/ref.typ
@@ -0,0 +1,10 @@
+#set page(width: auto, height: auto, margin: 2pt)
+
+$1.2 plus.minus 0.1$ \
+$2×10^(1.2)$
+
+$1,#h(0pt)2 plus.minus 0,#h(0pt)1$ \
+$2×10^(1","2)$ \
+
+$1,#h(0pt)234$ \
+$1"_"234$ \
diff --git a/tests/num/decimal-separator/test.typ b/tests/num/decimal-separator/test.typ
new file mode 100644
index 0000000..d020b5a
--- /dev/null
+++ b/tests/num/decimal-separator/test.typ
@@ -0,0 +1,16 @@
+#import "/src/zero.typ": *
+#set page(width: auto, height: auto, margin: 2pt)
+
+
+
+#num("1.2+-,1") \
+#num("2e1.2")
+
+#set-num(decimal-separator: ",")
+#num("1.2+-,1") \
+#num("2e1.2") 
+
+#set-num(decimal-separator: ".")
+
+#num("1.234", decimal-separator: ",") \
+#num("1.234", decimal-separator: "_") \
diff --git a/tests/num/self/ref/5.png b/tests/num/self/ref/5.png
index b3d47d7..776f862 100644
Binary files a/tests/num/self/ref/5.png and b/tests/num/self/ref/5.png differ