denominator (lower number) of a fraction appearing in the upper right corner of checks paid through the Federal Reserve System. The ABA transit number is the upper number. The routing symbol is a three- to four-digit number identifying the Federal Reserve district of the drawee (paying) bank, the Federal Reserve facility through which the check is collected, and the funds availability assigned by the Fed. Checks given immediate availability, indicated by a 0 as the final digit in the routing symbol, are payable the same day as presented to a Federal Reserve Bank for collection. A deferred availability check (identifiable by the numbers 1 through 9 in the final digit) is paid by a Federal Reserve Bank in two business days. For example: 50-226/ 213