diff --git a/web/demos b/web/demos
index ba3428c42..3865cf037 100644
--- a/web/demos
+++ b/web/demos
@@ -77,9 +77,9 @@ click on the name of the output file:
 
 17. TeX math in HTML:
 
-@   pandoc @@math.txt@@ -s -o @@mathDefault.html@@
-@   pandoc @@math.txt@@ -s -m -o @@mathAsciimathml.html@@
-@   pandoc @@math.txt@@ -s --mimetex=/cgi-bin/mimetex.cgi -o @@mathMimetex.html@@
-@   pandoc @@math.txt@@ -s --gladtex -o mathGladtex.htex
+@   pandoc @@math.text@@ -s -o @@mathDefault.html@@
+@   pandoc @@math.text@@ -s -m -o @@mathAsciimathml.html@@
+@   pandoc @@math.text@@ -s --mimetex=/cgi-bin/mimetex.cgi -o @@mathMimetex.html@@
+@   pandoc @@math.text@@ -s --gladtex -o mathGladtex.htex
 @   gladtex @@mathGladtex.htex@@   # produces @@mathGladtex.html@@
 
diff --git a/web/math.txt b/web/math.text
similarity index 100%
rename from web/math.txt
rename to web/math.text