vb.net combine random password

I need some help. I'm creating a login system in which has five buttons, each button will have two random numbers, these numbers will change every time the application loads, just like this picture.

See image

My question is what is the best way to check if the password is true or not?

• The password consists of four digits
• Once the user click on four buttons I'll have 8 different numbers

Let me know if my question isn't clear enough.