WhatDayWas

Helps you practice calculating weekdays for dates.

The WhatDay app helps you training in determining what weekday as specific day was on or will be on. It gives you a random date and asks you what weekday you think that was or will be and after you select a weekday it checks your answer and tells you whether you got it right.

It can also show you the calculation you could have used to determine the correct weekday, using the Doomsday rule.