I cannot find the serial number of my tablet, I did purchase a reburished tablet from a reputible source

You don't actually put it on the tablet. You sign into your itunes account from your tablet, then scratch the back of the card to reveal the serial number and type that into the itunes account and your money will appear on your account as a credit for you to make purchases. have fun.

Are you sure it is the serial numbers you are looking at and not the model numbers?

If you are and can verify that you are the riginal purchaser, you should contact by email the manufacturer. You will need to provide thm with the Serial # and probably the Model #.
If you bought it used, you will need to obtain this info from the original purchaser. The manufacturer will not give you the pin numbers without verification that you were the purchaser due to security issues which protect stored information. Good luck.

Return it to Walmart.

if you still have orig box, check labels... otherwise try taking back off, look under the battery

The serial number is located on a sticker adhered to the back of the tablet.

You can also find the serial number stored on the tablet. HP Support document

look on the box you bought it in or look through the setting in the tablet the serial number will be in one of the two places.

ereo I find the serial #

The serial number should be on the box it came in. It may also be in your tablet when you go into settings tap on "about tablet", it may be in that.