The first part of the hyphenated numerator in a bank fractional routing number stands for the city/state, notes BankersOnline.com. The second part of the numerator represents the American Bankers Association institution identifier, and the denominator is the Federal Reserve routing symbol.
Most checks have this fraction at the top right side of the check, explains BankersOnline.com. There are 28,000 financial institutions that are part of the Federal Reserve System. The fraction on the check identifies exactly from which bank the check is drawn and where it is located. In addition, the denominator indicates which of the 12 districts of the Federal Reserve services that particular bank. If a district is identified with a single-digit number, the zero in front of that number usually does not appear in the fractional form on the check. It does have to appear in the magnetic ink character recognition, or MICR, number at the bottom of the check.