The numbers on a baseball card contain the player's statistics and other basic facts. Reading them requires knowledge of the abbreviations for each statistic. The information may be different depending on the edition of the card.
The year and the team are listed on the left. The rest of the line lists statistics for that year. Some of the abbreviations are: G: games played with that team; AB: times at bat; R: runs scored; H: number of hits; 2B and 3B: doubles and triples; HR: home runs; RBI: runs batted in; BB: number of times walked and AVG: average. A pitcher's card will list these facts: W: wins; L: losses; S: saves; BB: walks and ERA: Earned Run Average.