Assistance for a person new to static IPs

I just got my business account with one static IP set up today. Phone support has been great, but I wanted to hit up these forums since I personally tend to work better through these. Here is my situation.

I got a static IP because I do computer security work as a consultant. When I am on a job, I want to be able to give the client my static IP address so that they can whitelist me. This means they add me to their protective systems (firewalls, IPS/IDS, etc) to allow me through so that I can test whatever they have hired me to test. What I want to confirm is the IP address I am to give to them.

I have been told the following from customer support:

IP Address: 50.196.225.xx

Gateway: 50.196.225.yy

When I go to a site like whatismyip.com, it says that my IP address is the gateway address of 50.196.225.yy. Is that how it should work? If that is correct, then that is the IP address I give out to the clients, right? And finally, if all that is correct, what do I use the 50.196.225.xx address for? 

Sorry for all the questions and they're probably pretty basic, but I want to understand so I get the information right to the clients I will be working with. Thank you.