If you have forgotten your passcode and get locked out of your iPad, you can take the following steps to unlock it:

  • Connect your iPad to whatever computer you normally use to sync with iTunes.
  • Right click on iPad in the left hand column of iTunes and click on “Backup”.
  • After the backup is finished running, select “Restore” to restore your iPad to the most recent backup date.

OR:

  • If you have never used iTunes unplug the cable from your iPad, but leave it plugged into your computer.
  • Press Sleep/Wake until the red slider appears and iPad turns off.
  • Press and hold the Home button, reconnect the USB cable to the iPad and wait for it to turn on.
  • Continue holding the Home button until you see “Connect to iTunes”, then release the Home button.
  • iTunes will alert you that it has detected the iPad in recovery mode. Click OK and then click Restore.

Source: Apple Support