The Math Cats site uses lots of Java applets.  Lots of other websites use Java applets, too.  If Java isn't working on your computer, we can help you fix it.

Why doesn't Java work on my computer right now??

Sun and Microsoft went to court, and Microsoft lost.
New versions of Windows no longer support Java.  Lots of people have upgraded Windows lately to fix security problems, and now they have lost the Windows version of Java.

How can I get Java to work on my computer??

You'll need to download and install Sun's Java plug-in: click here then click "Get It Now." If you are a student, please ask an adult for help.  If you are a teacher on a school network, please talk to the network administrator.

Good luck, and enjoy!