I apologize for posting such an untechnical question, but with responses it could surely be posed in a better form.
I'm a math noob, but I've seen (as we all have) a few examples of "connections" between different areas of math by way of an equality or some other relating device. An example is:
e^iπ + 1 = 0
These five constants serve different functions in a variety mathematical tasks. It seems to me that any constant is a "measurement" of some kind, which then begs the question "What is it a measurement of?"
Can you think of some places to start? If you have a "bridge" you like, post it.
This is discussed at length in the book Where Mathematics Comes From by Lakoff and Núñez.