The Training Roadmap

Master the algorithm step-by-step through focused mini-games

1.Foundations

Learn the core memorization building blocks.

Weekday number

Find the correct weekday number for a weekday

Leap years

Is the given year a leap year?

Anchor day

Find the correct anchor day for a given century

2.Math Components

Master the mental math tricks needed for the algorithm.

Divisor of 12

How many times can we divide the given number by 12

Modulo 12

Find the remainder after dividing by 12s

Divisor of 4

How many times can we divide the given number by 4

Sum modulo 12 and divisor of 4

Find the modulo 7 of the sum of the modulo 12 and its divisor of 4

3.Doomsday Core

Find the anchor doomsday for any month or year.

Doomsday dates (basic)

Find the doomsday for a given month in a non-leap year

Doomsday dates (advanced)

Find the doomsday for a given month and year

Doomsday of a year

Find the correct doomsday for the given year

4.Mastery

Put it all together and solve full dates instantly.

Putting it all together (easy)

Find the day of the week for the given date

Putting it all together (hard)

Find the day of the week for the given date