What is digital money and how is it different?

You hand over crinkly bills at the store, coins jingle in your pocket — that's money you can touch. But most money today never rustles or clinks at all. It lives as numbers glowing on screens, zipping between computers faster than you can blink. How does money work when it's made of nothing but digits?
Real paper money is a physical thing — the government prints it, you hold it, you pass it along. Digital money is just a number in a computer's memory saying "this account has $47.23." The bank's computer keeps score. When you buy something, the computer subtracts from your number and adds to the store's number. No paper ever moves.
