Calendar Calculation quiz

More questions about Calendar Calculation

These visible examples show the question style. LearnClash turns the full topic into ranked duels and spaced repetition.

1. 1 Easy

   In leap years, which month gets extended with a twenty-ninth calendar day?

   Answer: February

   Why: Romans originally placed the intercalary day in February because it was the final month of the archaic Roman calendar.

2. 2 Medium

   What does Zeller's congruence formula calculate for any Gregorian date?

   Answer: Day of week

   Why: Christian Zeller published it in 1882, and its result counts from 0 for Saturday, so 1 means Sunday.

3. 3 Hard

   What is the anchor day for the 1900s in the Doomsday rule?

   Answer: Wednesday

   Why: The Doomsday rule uses easy-to-remember dates like 4/4, 6/6, and 8/8 which always land on the same weekday.

4. 4 Easy

   Which divisor does modular arithmetic use for days of the week?

   Answer: 7

   Why: A common year is 365 days, which is 52 weeks plus one, so every date lands one weekday later the following year.

5. 5 Medium

   In Zeller's congruence, which month counts as month 13?

   Answer: January

   Why: To simplify leap year math, Zeller's congruence treats January and February as months 13 and 14 of the preceding year.

6. 6 Hard

   What does the epact measure in ecclesiastical calendar calculations?

   Answer: Age of moon

   Why: A 12-month lunar year falls 11 days short of the solar year, so the epact grows by 11 each year and sheds 30 whenever it reaches a full lunation.