Calendar and Time Calculation

Calendar and Time Calculation

One week: 7 days - Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday.

One month: about 4 weeks, between 28 and 31 days.

One year: 12 months.

Each of the months is assigned a number.


Calendar and Time Calculation

In this article, you will learn to understand the calendar and calculate time correctly! You can calculate time in days, weeks, months, and even years! Isn't that amazing?

The first step you need is to know how to read the calendar.

We have attached a nice calendar for you here:



There are 7 days in a week: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday.

Practice questions on days and weeks:

The students from the science class went on a fun trip from Sunday morning and returned Thursday night.

How many days did the trip last? Solution:

The trip lasted 5 days - Sunday, Monday, Tuesday, Wednesday, and Thursday.

Another question:

Tatiana went for a walk to the north from Wednesday and returned the following Tuesday.

Did Tatiana's trip last more than a week or less than a week?


If Tatiana's trip lasted a week, she would have to return the following Wednesday.

Since she returned the day before, the trip lasted less than a week.

(only 6 days instead of 7 days)

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A month lasts about 30 days and contains about 4 weeks.


Number of days in a year

The duration of a normal year is 365 days.

Every 4 years there is a leap year in which there is one more day.

A year is considered the time it takes for the Earth to orbit around the sun and is measured in 365.25 days.

What is a leap year?

A leap year is a year in which we add a day to the year to synchronize the calendar with the Earth's revolutions around the sun.

Therefore, once every 4 years a day is added to the month of February, and instead of 28 days, it will have 29 days.

Unless the year number is divisible by 100, then we will not add a day.

If it is divisible by 100 but also divisible by 400, we will add a day.

There are 12 months in a year.

Each month has a different number of days.

Here is a chart that will summarize everything you need to know:

  1. January - 31 days
  2. February - 28 days in most years (29 days in a leap year)
  3. March - 31 days
  4. April - 30 days
  5. May - 31 days
  6. June - 30 days
  7. July - 31 days
  8. August - 31 days
  9. September - 30 days
  10. October - 31 days
  11. November - 30 days
  12. December - 31 days

The differences between the Gregorian calendar and the Jewish calendar

The Gregorian calendar always has 12 months.

The number of days it has is 365, each day is numbered with numbers and every 4 years there is a leap year.

Most countries in the world use the Gregorian calendar which is calculated from the days of Julius Caesar in Rome and is considered a more accurate solar calendar.

On the other hand, the Jewish calendar is calculated according to the renewal of the sun and the moon, and each day is marked according to the Hebrew letters.

The day when the moon is not seen, the month is started to be counted and thus the first day of a Hebrew month is the day when the moon is not seen.

Generally, about two months after the start of the Jewish calendar, the Gregorian calendar will be applied and in this way, it is possible to synchronize them.


Nadia went on vacation to Italy from June to August.

How many months did Nadia's vacation last?


We must remember that June is identified by the number 6 and August by the number 8.

Therefore, we calculate: 86=28-6=2
Nadia's vacation lasted two months.

Another question:

If today is 1212 of May, what date will it be in 88 months?


We must count 88 months from May, the fifth month. If we calculate: 5+8=135+8=13 we get 1313.

This tells us that the year lasted until month 1212 and month 1313 is actually January of the following year.

Therefore, a period of 88 months will lead you to the date 1212 of January of the following year.

Another question:

The company "Joyful Furniture" closed for vacation with all employees from 1212 to 2121 of July.

How many days did the vacation last?


We calculate the number of days as a simple exercise:


The vacation lasted 99 days.

Now we move on to a complex question about the years:

Bernarda is 1212 years old, Gal is 1515 years old, and Naomi is 4040 years old.

Bernarda was born in 20072007.

  1. What year was Gal born?
    Solution: in 20042004.

Explanation: it seems that the only figure we have to find information about the years is that Bernarda was born in 20072007 and is 1212 years old.

Gal is older than Bernarda by 33 years. This means she was born 33 years before her. That is, in the year 20042004.

2. What year was Naomi born?
Solution: in 19791979.

Explanation: we calculate how many years older Naomi is than Bernarda.
Naomi is older than Bernarda by 2828 years.

Bernarda was born in 20072007 and Naomi 2828 years before her.
Therefore, the year Naomi was born is 19791979.

 200728=1979 2007-28=1979

3. What year is it today? (According to the initial question data)
Solution: 20192019.