[Q] How do I know which one ? topic

Good Morning everyone. So I go to pay my Sprint bill, then they tell me I can take home a Galaxy Tab 3 home for free, so I did. My question is, I want to root it, but I'm not sure which one I have. How do I find this out. I've seen the forums for different versions and I'm just trying to figure out which one it is. Thanks for any help.