Batting Average - Divide the total number of hits collected by a player by the total number of at bats. Example: Player A is 12-for-40, or hit .300.
Slugging Percentage - Divide the number of total bases by the total number of at bats. Example: Player A's 12 hits include six singles (6), one double (2), two triples (6) and three home runs (12) for a total of 26 total bases in 40 at bats and a .650 slugging percentage.
On-Base Percentage - Divide the total of hits, all bases on balls and hit by pitch by the total of at bats, all bases on balls, hit by pitch and sacrifice flies.
Earned Run Average - The total number of earned runs allowed by a pitcher is divided by the total number of innings pitched and then multiplied by nine for his per-game average. Example: Pitcher B has allowed 12 earned runs in 45 innings of work for a 2.40 ERA.
Fielding Average - The sum of putouts and assists is divided by the sum of putouts, assists and errors. Example: Player C has made 16 putouts and 24 assists and two errors. that's 40 putouts and assists divided by 42 total chances for a fielding average of .952.
Magic Number - Determine the number of games yet to be played by the division leader, add one, then subtract the number of games ahead in the loss column of the standings from the closet opponent.