If you can't find them on any of your homescreens or app folders, and you can't find them via the spotlight search screen (drag down the centre of the home screen down), then are they hidden by Settings > General > Restrictions > Installing Apps, iTunes and Safari being set 'off' ?
If not then have you tried a reset to see if you can find them after the iPad has restarted ? Press and hold both the sleep and home buttons for about 10 to 15 seconds (ignore the red slider), after which the Apple logo should appear - you won't lose any content, it's the iPad equivalent of a reboot.