Calendar and Dates (Grade 4)
Understanding calendars and dates is an essential life skill. In Class 4, you learn about the number of days in each month, leap years, reading calendars, and calculating the number of days between two dates.
Calendars help us plan events, remember important dates, and understand the passage of time. Every student must know how many days each month has and what makes a year a leap year.
What is Calendar and Dates - Class 4 Maths (Time)?
Key facts about the calendar:
- A year has 12 months and 365 days (366 in a leap year).
- A week has 7 days.
- A year has 52 weeks and 1 day (or 52 weeks and 2 days in a leap year).
Days in each month:
| Month | Days | Month | Days |
|---|---|---|---|
| January | 31 | July | 31 |
| February | 28/29 | August | 31 |
| March | 31 | September | 30 |
| April | 30 | October | 31 |
| May | 31 | November | 30 |
| June | 30 | December | 31 |
Leap year: Divisible by 4 (except century years: must be divisible by 400)
February has 29 days in a leap year, 28 days otherwise.
Solved Examples
Example 1: Example 1: Days in a Month
Problem: How many days does September have?
Solution:
Use the rhyme: "30 days has September, April, June, and November."
Answer: September has 30 days.
Example 2: Example 2: Leap Year Check
Problem: Is 2024 a leap year?
Solution:
2024 ÷ 4 = 506 (exact division, no remainder).
Answer: Yes, 2024 is a leap year. February 2024 has 29 days.
Example 3: Example 3: Century Year Check
Problem: Is 1900 a leap year?
Solution:
1900 is divisible by 4 (1900 ÷ 4 = 475), but it is a century year. Check divisibility by 400: 1900 ÷ 400 = 4.75 (not exact).
Answer: No, 1900 is not a leap year. (But 2000 is, since 2000 ÷ 400 = 5 exactly.)
Example 4: Example 4: Finding Days Between Dates
Problem: How many days are there from March 15 to April 10?
Solution:
Step 1: Days left in March = 31 − 15 = 16 days
Step 2: Days in April up to the 10th = 10 days
Step 3: Total = 16 + 10 = 26 days
Answer: 26 days
Example 5: Example 5: What Day of the Week?
Problem: If January 1 is a Monday, what day is January 15?
Solution:
Step 1: From Jan 1 to Jan 15 = 14 days = 2 weeks exactly.
Step 2: 2 complete weeks from Monday → Monday again.
Answer: January 15 is a Monday.
Example 6: Example 6: Total Days in a Year
Problem: How many days are in the year 2025?
Solution:
2025 ÷ 4 = 506.25 (not exact) → Not a leap year.
Answer: 2025 has 365 days.
Example 7: Example 7: Word Problem — Birthday
Problem: Aditi's birthday is on August 22 and Kavi's is on October 5. How many days apart are their birthdays?
Solution:
Step 1: Remaining days in August from 22nd = 31 − 22 = 9
Step 2: All of September = 30 days
Step 3: October 1 to 5 = 5 days
Step 4: Total = 9 + 30 + 5 = 44 days
Answer: Their birthdays are 44 days apart.
Example 8: Example 8: Weeks and Days
Problem: Convert 50 days into weeks and days.
Solution:
50 ÷ 7 = 7 weeks and 1 day (7 × 7 = 49, remainder 1)
Answer: 7 weeks and 1 day
Example 9: Example 9: Knuckle Method
Problem: Use the knuckle method to find months with 31 days.
Solution:
Make a fist. Starting from the left, count the knuckles (bumps) and valleys:
Jan (knuckle-31), Feb (valley-28/29), Mar (knuckle-31), Apr (valley-30), May (knuckle-31), Jun (valley-30), Jul (knuckle-31), then start again: Aug (knuckle-31), Sep (valley-30), Oct (knuckle-31), Nov (valley-30), Dec (knuckle-31).
Answer: Months on knuckles have 31 days; months in valleys have 30 (or 28/29 for February).
Key Points to Remember
- Months with 31 days: January, March, May, July, August, October, December.
- Months with 30 days: April, June, September, November.
- February: 28 days (29 in a leap year).
- A leap year is divisible by 4. Century years must be divisible by 400.
- A year has 365 days (366 in a leap year).
- To find days between dates: count remaining days in the first month, add full months, then add days in the last month.
Practice Problems
- How many days does November have?
- Is 2028 a leap year? How many days will February have?
- How many days are there from June 20 to August 5?
- If March 1 is a Wednesday, what day is March 22?
- Convert 100 days into weeks and days.
- Rahul's exam starts on April 15 and ends on May 10. How many days is the exam period?
- Is the year 2100 a leap year? Explain.
Frequently Asked Questions
Q1. How many days does February have?
February has 28 days in a common year and 29 days in a leap year.
Q2. How do you check if a year is a leap year?
Divide by 4. If it divides exactly, it is usually a leap year. Exception: century years (1800, 1900, 2100) must be divisible by 400. So 2000 is a leap year, but 1900 is not.
Q3. What is the knuckle method for remembering days in months?
Make a fist and count across the knuckles. Knuckles (bumps) are months with 31 days, valleys between knuckles are months with 30 days (or 28/29 for February).
Q4. How many weeks are in a year?
A year has 52 weeks and 1 extra day (365 ÷ 7 = 52 remainder 1). In a leap year, there are 52 weeks and 2 extra days.
Q5. How do you find the number of days between two dates?
Count the remaining days in the starting month, add the days for each complete month in between, then add the days in the final month.
Q6. Which months have 30 days?
April, June, September, and November — remembered by the rhyme '30 days has September, April, June, and November.'
Q7. What is special about the year 2000?
2000 was a leap year because it is divisible by 400. This is special because most century years (1700, 1800, 1900) are not leap years.
Q8. Is calendar and dates part of NCERT Class 4?
Yes, reading calendars, knowing days in each month, and understanding leap years are part of the CBSE/NCERT Class 4 curriculum under the Time chapter.
