also what is the formula of computing the approximate number of days?

To compute the approximate number of days, you need to know the starting date and the ending date. The formula involves subtracting the starting date from the ending date and considering any leap years that might be present.

Here is the formula for computing the approximate number of days:
1. Calculate the number of years between the starting date and the ending date, excluding the leap years. Multiply this number by 365.
2. Count the number of leap years between the starting year and the ending year (including the ending year if it is a leap year). Multiply this number by 366.
3. Add the results from steps 1 and 2 to get the total number of days.

Here's an example to illustrate the process:
Let's say the starting date is January 1, 2018, and the ending date is October 12, 2021.

Step 1:
Calculate the number of years between 2018 and 2021, excluding leap years: 2021 - 2018 = 3 years.
Multiply this by 365: 3 * 365 = 1095 days.

Step 2:
Count the number of leap years between 2018 and 2021: 2019 (not a leap year), 2020 (leap year), 2021 (not a leap year). So there is 1 leap year.
Multiply this by 366: 1 * 366 = 366 days.

Step 3:
Add the results from steps 1 and 2: 1095 + 366 = 1461 days.

Thus, the approximate number of days between January 1, 2018, and October 12, 2021, is 1461 days.