The IMEI number identifies the individual device as well as a serial number. *#06# on the dialer should give it to you. So should Settings/General/About device/Status, then scroll down to IMEI. (The serial number should be a few lines further down.)
Welcome to Android Central! If you're adventurous, you could try popping off the back cover of the device--the SN might be printed somewhere inside. However, this might also void the warranty.
If you look at the side of the tablet opposite of the on button (and others) it's printed on there. It took me several tries to find because it's only a couple of shades different than the case. Good Luck!