Check the version of an app installed on iPad
iOS provides a list with all installed Apps and their memory usage. Tapping on any App on that list will, besides giving you the option to delete it, display the name, the version, its size and how much memory it's using.

The path to access this list has changed through the iOS versions:

iOS 11: Settings / General / iPad Storage

iOS 9: Settings / General / Storage and iCloud usage / Manage Storage

iOS 8: Settings / General / Usage / Manage Storage

iOS 7: Settings / General / Usage