Date manager has two functions. First, it tells what day of the week corresponds to a given date. For example, if you want to know what day your birthday will be, type in the date (e.g. 17/02/2013) and the app will reveal it is going to be on Friday. In addition the app calculates how many days are comprised between two dates. For example, if you want to know how long your vacation will be, insert start date (e.g. 12/08/2013) and second date (e.g. 03/09/2013) and the app will tell you it is 22 days.