Birthday Weekday
Birthday Weekday problems ask for the day of the week on which a person's birthday falls in a given year, often compared to another year. These problems test your ability to calculate day shifts across years considering leap years.
What You'll Learn
Introduction to Birthday Weekday
Birthday Weekday problems ask for the day of the week on which a person's birthday falls in a given year, often compared to another year. These problems test your ability to calculate day shifts across years considering leap years.
Prerequisites
How to Solve Birthday Weekday Problems
Step 1: Identify the birthday date (month and day) and the two years
Step 2: Calculate the day of week for the birthday in the reference year
Step 3: Count the number of years between the two dates
Step 4: Count how many leap days (Feb 29) occur between the two birthdays
Step 5: Total odd days = number of years + number of leap days crossed
Step 6: Add odd days to reference weekday (mod 7) to get target weekday
Step 7: If birthday is Jan 1-Feb 28, leap day in between doesn't affect? Actually careful
Example Problem
Example: A person's birthday is on March 15. If March 15, 2023 was a Wednesday, what day will March 15, 2024 be? Solution: Step 1: Birthday: March 15 Step 2: Reference: 2023, Wednesday Step 3: Years between = 1 Step 4: Leap days crossed: Feb 29, 2024 occurs between March 15, 2023 and March 15, 2024? Yes (Feb 29 is after March 15, 2023 and before March 15, 2024) Step 5: Odd days = 1 (year) + 1 (leap) = 2 Step 6: Wednesday + 2 days = Friday Answer: Friday Example 2: Birthday on January 15. Jan 15, 2023 was Sunday. What day is Jan 15, 2024? Solution: Years=1, leap day crossed? Feb 29 is after Jan 15, so not crossed (birthday is before Feb 29). Odd days = 1 → Monday Answer: Monday
Pro Tips & Tricks
- For birthdays on or after March 1: add +1 for each leap year in between
- For birthdays in Jan/Feb: leap year effect applies from the previous year
- Formula: Shift = (Number of years) + (Number of Feb 29s between birthdays)
- A person's birthday shifts by 1 day each normal year, 2 days after leap year (for March-Dec birthdays)
- For Jan/Feb birthdays, shift is 1 day, except when crossing from leap year to next year? Actually careful
- Age affects weekday: after 10 years, shift = 10 + number of leap years in that decade
Shortcut Methods to Solve Faster
Common Mistakes to Avoid
Practice Worksheets
Practice makes perfect! Work through these worksheets to master Birthday Weekday. Each worksheet contains 20 questions with detailed explanations. Start from Worksheet 1 and progress through increasing difficulty levels.
Exam Importance
Birthday Weekday is an important topic for various competitive exams. Here's how frequently it appears:
Ready to Master Birthday Weekday?
Start with Worksheet 1 and work your way up to expert level! Each worksheet includes: