DateGuessr - Train Your Mind by Calculating Days of the Week

Did you know you can mentally calculate what day of the week any historical date fell on? DateGuessr teaches you this fascinating mathematical algorithm and helps you master it through constant practice.

? What is DateGuessr?

DateGuessr is an educational app designed to teach and help you practice mental calculation of the day of the week using Zeller's algorithm. With this technique, you can instantly know that July 20, 1969 (the moon landing) was a Sunday, or that your birthday in 2004 fell on a Tuesday, all in your head!

? Game Modes

1. Interactive Tutorial

Learn the method step-by-step with our 5-step tutorial:
- Memorize the month and century tables
- Understand the mathematical formula
- Practice calculating modulo 7
- Identify the resulting day
- Discover tricks to calculate faster

2. Free Practice

Train without time pressure with custom settings:
- Select a range of years
- Filter by specific months
- Activate numerical hints on buttons
- View the solution step-by-step
- Multiple configurable attempts
- Complete history of your practice

3. Challenge Mode

Test your speed in three difficulty levels:
- Easy: 3 minutes initial, +45 seconds per correct answer, 2 points
- Medium: 2:30 minutes, +30 seconds per correct answer, 5 points
- Hard: 1 minute, +10 seconds per correct answer, 10 points
- Each mistake subtracts 15 seconds
- Survive as long as possible

4. Historical Date Groups

Learn history while you practice:
- 20 world historical dates (moon landing, fall of the Berlin Wall, etc.)
- 20 celebrity births (Einstein, Shakespeare, Mozart, etc.)
- Create your own custom groups
- Share groups with friends using encrypted codes
- Import groups from other users

⭐ Point System and Gamification

Earn virtual points while you practice:
- 1 point for each correct answer in Free Practice
- 2-10 points in Challenge Mode depending on difficulty
- Use 30,000 points to permanently disable ads
- Track your accuracy, streaks, and stats

? Educational Features

Full Customization:
- Set specific date ranges
- Select months to practice
- Enable/Disable visual aids
- Adjust difficulty to your level

Educational Feedback:
- Step-by-step solution visualization
- Tips Number buttons
- Explanation of each component of the formula
- History to identify areas for improvement

Historical Content:
- 40 curated historical dates
- Information on important events
- Learn history while training your mind

? Advantages of DateGuessr

✅ Completely offline - Works without internet
✅ No registration - Start playing immediately
✅ Total privacy - Data saved only on your device
✅ No real purchases - Everything is unlocked through play
✅ Educational and fun - Learn while having fun
✅ Suitable for all ages - Appropriate and educational content

? Why Learn This Algorithm?

Mental Benefits:
- Train your memory (month and century tables)
- Improve mental calculations
- Develop math skills
- Impress friends and family

Practical Uses:
- Verify historical dates
- Plan future events
- Mathematical entertainment
- Unique conversation starter

Download DateGuessr and discover the fascinating world of mental date calculations.
Turn your brain into a perpetual calendar!