--- loncom/homework/default_homework.lcpm	2008/09/27 07:26:45	1.141
+++ loncom/homework/default_homework.lcpm	2008/11/26 18:11:52	1.142
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA 
 # used by lonxml::xmlparse() as input variable $safeinit to Apache::run::run()
 #
-# $Id: default_homework.lcpm,v 1.141 2008/09/27 07:26:45 raeburn Exp $
+# $Id: default_homework.lcpm,v 1.142 2008/11/26 18:11:52 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -217,7 +217,13 @@ sub caparesponse_check {
 
     my $reterror="";
     my $result;
-    if ((($type eq '9') || ($type eq '8')) && ($response=~/\=/)) { return ('BAD_FORMULA','Please submit just an expression, not an equation.'); }
+    if (($type eq '9') || ($type eq '8')) {
+        if ($response=~/\=/) {
+            return ('BAD_FORMULA','Please submit just an expression, not an equation.');
+        } elsif ($response =~ /\,/) {
+            return ('BAD_FORMULA');
+        }
+    }
     if ($type eq '9') {
       $result = &maxima_check(&maxima_cas_formula_fix($response),&maxima_cas_formula_fix($answer),\$reterror);
     } else {