Super Bowl LIX kicks off on Sunday. What number is that, though? Here's how to use Roman numerals and why the NFL uses them for the championship game.

The Super Bowl uses Roman numerals to identify each version of the game, which can confuse viewers trying to read the old numerical system.

"The Roman numerals were adopted to clarify any confusion that may occur because the NFL championship game — the Super Bowl — is played in the year following a chronologically recorded season.