diff --git a/lisp/calc/calc.el b/lisp/calc/calc.el
index b519559330e..648cb7bb807 100644
--- a/lisp/calc/calc.el
+++ b/lisp/calc/calc.el
@@ -2925,6 +2925,7 @@ the United States."
 
 
 
+(defvar math-comp-selected)
 (defvar calc-selection-cache-entry)
 ;;; Format the number A as a string.  [X N; X Z] [Public]
 (defun math-format-stack-value (entry)