My iOS app version numbers conform to the format "1.2.3 (1004)", where "1" is the major version, "2" is the minor version, "3" is the patch version, and "1004" is the overall build number. "1.2.3" is a single "Version" text field in Xcode, while "1004" is a single "Build" text field in Xcode.
To make working with app version numbers easier, I've created a utility class that reads the version strings from the info.plist and splits it into values that conform the description that I listed about. It also creates a friendlier formatted string of the version info that you can display in your app.