What OS? Is the game written for that OS?
When you say the game is on a disc, what kind of disc? Do you mean it's on an optical disc such as a CD/DVD?
If the tablet is a Windows tablet, and you have a Windows game that is on a CD/DVD, then you should be able get an external optical drive that will plug into the USB port on the tablet. You'll then be able to install the game to your tablet. You'll most likely need an external drive with it's own power supply since often the USB port on a tablet can't provide enough power to power an external drive.
If you have a desktop or laptop PC with an optical drive then you could share that drive over a network and install to your tablet from the shared drive.