Check Routing Symbol
  
You write a check to your buddy Edwuster Weeblewizzle. He deposits it. The money moves out of your account and into his. But how does the bank know where to get your money from?
The routing information.
On every check, there's routing information (including the routing symbol) that shows where the money for the check is supposed to come from.
The routing number identifies the bank. Then there's your bank account number, which shows what account at the bank has the money meant to cover the check. Then there's the check number, which helps track the check.
Edwuster's bank uses this info to pinpoint where the money comes from. Some computers talk to each other, and boom...Eddie gets his money. Excellent. No angry phone calls from Eddie.