diff --git a/ChangeLog b/ChangeLog
index c0fe24965..2ae9ccade 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2022-11-23  Daniel Shahaf  <d.s@daniel.shahaf.name>
+
+	* unposted (cf. 51016): Test/C01arith.ztst: Add a test case
+	for underscore-followed-by-digits in math context.
+
 2022-11-17  Oliver Kiddle  <opk@zsh.org>
 
 	* unposted (c.f. Norikatsu Shigemura: github #96):
diff --git a/Test/C01arith.ztst b/Test/C01arith.ztst
index d0092fefa..ba9c65e5b 100644
--- a/Test/C01arith.ztst
+++ b/Test/C01arith.ztst
@@ -251,6 +251,14 @@
 >5000
 >255
 
+ set -- {101..120}
+ _10=42
+ echo $_10 : $1_0
+ echo $(( _10 )) : $(( 1_0 ))
+0:underscores in front of a numeric identifier is not a math constant
+>42 : 101_0
+>42 : 10
+
   # Force floating point.
   for expr in "3/4" "0x100/0x200" "0x30/0x10"; do
     print $(( $expr ))