bat five hundred
To be correct or successful around half of the time. Taken from baseball terminology, referring to the average times a player makes a hit when at bat (i.e. the batting average). One hit for every two at-bats is a .500 batting average. Primarily heard in US, South Africa. That math exam didn't go so well, I only batted five hundred or so. The market is so hit and miss at the moment, you can only really expect to be batting five hundred at best.