OtterDay: Calendar Logic Game

Can you name the weekday of any date? OtterDay turns calendar calculation into a fast, satisfying logic game. Learn a reliable mental method step by step, then practice until you can find the right weekday in seconds, without checking a calendar. Every round challenges logic, memory, number sense, and mental math. Futuristic otter guides teach the method one piece at a time. Start with recent dates, unlock wider ranges across centuries, and train for speed and precision. Why you'll keep playing: • Guided lessons for the calendar method • Written and spoken-date challenges • Speed and precision training • Personal statistics and progress tracking • Achievements for accuracy, endurance, and fast answers • Flexible difficulty for quick practice or serious mastery Made for curious minds who enjoy Sudoku, logic puzzles, mental math, number games, brain training, and clever systems. The method is related to John Conway's Doomsday Algorithm, presented as a focused puzzle adventure instead of a dry lesson.