Better Explained:

Whoa. There’s so much information conveyed in a simple numbering scheme! Without looking at a map, I know I can drive from Seattle to Boston on I-90. Maybe I’ll take I-95 South when I’m there and make my way to Florida. On the way I’ll take I-10 West, over to LA, then drive up I-5 North back to Seattle.

How does this work?

We have a concept of a number, and all its properties (even/odd, size, number of digits…)

We noticed a real-world object (a highway) that had various properties (North/South, position, major/minor)

We associated the properties of the number to the properties of the object