1. How did you take Year no. as 6?

To determine the year number, we need to consider the reference point or the starting year. In the Gregorian calendar, the most widely used calendar system, the starting year is considered as 1 AD (Anno Domini).

In this case, if the reference point is not mentioned, we can assume the starting year as 1 AD. Therefore, the year number can be calculated by subtracting 1 from the given year.

For example, if the given year is 7, the year number would be 7 - 1 = 6.

2. How did you take month May as 1 instead of 5?

When solving problems on calendars, we often use a concept called the Zeller's Congruence, which helps us determine the day of the week for any given date. According to Zeller's Congruence, we consider January and February as the 13th and 14th month of the previous year respectively.

In this case, if the given month is May, we need to consider it as the 1st month of the following year. Therefore, we subtract 12 from the given month number to get the adjusted month number.

For example, if the given month is 5, the adjusted month number would be 5 - 12 = -7.

To make the adjusted month number positive, we add 12 to it. So, -7 + 12 = 5. Hence, May is represented by the month number 5 in this calculation.

Related: How to solve problems on Calendar (Part - 1)?

To solve problems on the calendar, there are a few key concepts and formulas that can be useful. Here is a step-by-step guide on solving calendar problems:

1. Determine the reference point: Identify the starting year or the reference point mentioned in the problem. If it is not specified, consider the starting year as 1 AD.

2. Calculate the year number: Subtract 1 from the given year to find the year number. This will give you the number of years that have passed since the reference point.

3. Adjust the month number: If the given month is January or February, consider it as the 13th or 14th month of the previous year respectively. Subtract 12 from the month number and add 12 if it is negative to get the adjusted month number.

4. Identify the day of the week: Use Zeller's Congruence formula to determine the day of the week for the given date. The formula is as follows:

h = (q + [(13(m + 1))/5] + K + (K/4) + (J/4) + 5J) % 7

Where:
q = day of the month
m = adjusted month number
K = last two digits of the year number
J = first two digits of the year number

The result of the formula will be a number from 0 to 6, representing the days of the week starting from Sunday (0) to Saturday (6).

5. Interpret the result: Based on the number obtained from the formula, determine the corresponding day of the week. For example, if the result is 0, it represents Sunday.

By following these steps and using the appropriate formulas, you can solve problems on calendars effectively.