Figuring out baseball statistics can sometimes be...

Figuring out baseball statistics can sometimes be frustrating, so here is a guide to calculating three of the more obscure categories:

* On-base percentage--Add the total number of hits, walks and hit by pitches and divide by the total of at-bats, walks, hit by pitches and sacrifice flies.

* Slugging percentage--Divide the total bases from all hits (a single is worth one base, a double is worth two, etc.) by the total number of at-bats.

* Earned-run average--Multiply earned runs by nine and divide by innings pitched.