Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
Unfortunately there is NO way to retrieve that passcode or get back to your iPad without the passcode. Your only option is to force-restore the iPad to factory settings through iTunes by putting it to DFU (Device Firmware Upgrade) mode, which will erase everything from it. This is how Apple designed it to protect the information of their users.
But if you've backed up your iPad to iTunes on your computer or iCloud, then you can restore all your data back after restoring your iPad from iTunes/iCloud. You can also redownload all your past purchases for free using the same account.
Follow the steps below to restore your iPad by putting it to DFU Mode.
First download and install latest iTunes on your computer from here : https://www.apple.com/itunes/download/
Then connect the iPad to your computer with the USB Cable.
Open iTunes application on your computer.
On your iPad press and hold the Home button and the Power button at the same time.
After EXACTLY 8 seconds release the Power button. Continue holding the home button until your iTunes shows a message telling you that it has detected an iPad in recovery mode.
Click OK or Restore
Note : Put it to DFU Mode while connected to computer and also in DFU Mode your iPad will remain blank and will be unresponsive. It is normal. If it is not showing blank/black screen, then repeat the steps again. Timing is critical when you put it to DFU Mode. So keep trying until it goes to DFU Mode. And it will take a while to restore it.
Remember, it may take a while to restore the iPad (the iOS firmware has to be downloaded, you will see the Download button at the top right corner of iTunes screen. Click it to see the time remaining)
Please let me know if that didn't work, so I will continue to help you until we fix the problem.
Not sure why it asked you to download iCloud. If you are in iTunes, check if the firmware is being Downloaded. Click the Download button (the down arrow button) at top right and do you see the Downloading progress ?
Your iPad will be unresponsive and shows black screen until the firmware is downloaded and installed to your iPad
Your iPad is in correct mode (to get out of DFU Mode, you can hold down both Power and Home button for 10 seconds).
You have to uninstall iTunes and all iTunes components from your computer completely and reinstall iTunes. Follow the instructions in here to remove iTunes and all its components completely --> https://support.apple.com/en-in/HT204275
Then download and reinstall iTunes from here --> http://www.apple.com/itunes/download/
Let me know how it goes.
There is another way. Disconnect your iPad from your computer and remove the USB cable. Then press and hold down both Home and Power button at the same time until you see the Apple logo. Release the buttons and let it boot. This will boot into locked or passcode screen. Now, do you see the WiFi icon at top left ? Is it connected to WiFi ?
If so, then on your computer go to www.icloud.com
Login to your iCloud account. Then click Find My iPhone/iPad option. Then select your iPad under All Devices. Then erase it. This will remotely erase the iPad without iTunes. This will not work if the iPad is not connected to WiFi or internet.
If it doesn't work, then you have to restore it from your computer using iTunes. So put it to DFU mode again and restore from iTunes.
How is it going Dave ?