If you want to check your Ubuntu or Linux Mint version, you can open up a terminal and type the command:

lsb_release -a

You'll see some output like the following:

 

me@Achieve ~ $ lsb_release -a

No LSB modules are available.

Distributor ID:LinuxMint

Description:Linux Mint 18 Sarah

Release:18

Codename:sarah

 

You can see from the above output that I am using Linux Mint and it shows that I am using Linux Mint 18.