Remember how I said that all even numbers are the same as all whole numbers. It sounds pretty confusing, here is a little story to help you picture it. 

There is a hotel that is called Hilbert's Hotel. It has an infinity amount of rooms. Each room is taken up by one guest. Sounds like it is a full house right? . . . No. Infinity pretty much goes against common sense. Back to the story, There is another person that wants to stay. In order for them to have a room, everyone moves up a room. So the person in room one, would have to move to room 2. Makes sense?