Place
Understanding the "place" of each number is crucial! First, it's important to know that number can be also called digit. And that you cannot write more than one digit in each place. So to make it fun we make up our neighborhood. In his case, numbers are the ones that live there, and they do not like to share there place. As the neighbors come over to live there they get their own space.
In 2nd grade we learn numbers all the way to the thousands! =)