In the modern world, it is customary to count time, on the one hand, by months and days, on the other, by days of the week. There are times when it is necessary to determine which day of the week a particular date falls on.
The easiest way to find out the ratio of numbers to days of the week is, of course, to look at the calendar. However, it is not always at hand, and sometimes it comes to a very distant date in the future, falling on another year.
Self-counting in your mind
The easiest way to find out what day of the week a number falls on is based on the number of days in the week. Traditionally, a seven-day week is used, therefore, it is necessary to subtract the number 7 from the serial number of the number, repeat it again, and again - until the result is in the immediate vicinity of today, then it will not be difficult to find out what day of the week it is. The same will be the day of the week for the date in question.
For example, today is May 2, but you need to find out the day of the week, which will fall on May 31. From 31 it is necessary to subtract 7, it turns out 23, from 23 again 7 is subtracted, it turns out 16, then 16 - 7 = 9, 9 - 7 = 2.
May 2 is Friday, so May 31 will also be Friday.
You can also go the opposite way, adding 7 to today's number over and over again until the result approaches the desired date. For example, May 5 is Monday, but you need to find out what day of the week May 28 will be. 5 + 7 = 12, 12 + 7 = 19, 19 + 7 = 26. Knowing that May 26 is Monday, it is easy to answer that May 28 is Wednesday.
Some difficulty arises only "at the junction" of the months. It is better to "calculate" such moments by day, and then continue to apply the described technique.
System "Vruceleto"
Such a system was once used by circus performers, "guessing" (and in reality - calculating) the days of the week by dates for the amusement of the public, and the system works for any year. Nothing prevents you from using it for practical purposes.
Each month corresponds to a certain day; to memorize these numbers, mnemonic words and phrases were used: January - 1 (1st month of the year), February - 4 (fiercely - a word of 4 letters), March - 4 (4 letters in the name of the month), April - 0 (zero temperature), May -2 (May 1), June - 5 (hot - 5 letters), July - 0 (not a drop of rain), August - 3 (3rd summer month), September - 6 (small rain - 6 letters in the word "small"), October - 1 (one leaf on a branch), November - 4 (snow), December - 6 (prepare the sleigh in the summer, and the cart in the winter - 6 letters in the word "cart") …
These numbers were used in the counting system. The last two digits of the year were divided by 12, the remainder was divided by 4 and the result of the first division and the remainders from both divisions were added. If the resulting number is less than seven, it is remembered, if it is 7 or more, it is divided by 3 and the remainder is remembered. The number corresponding to the month is added to this number or the remainder. If the result is less than seven - remember, if 7 or more - divide by 7 and remember the remainder.
The number of the day is added to the resulting number, if the result is more than seven, it is again divided by 7 and the remainder is remembered. The resulting number corresponds to the day of the week according to the following scheme: Saturday - 0, Sunday - 1, Monday - 2, etc. For example, you need to establish what day of the week was June 7, 2016.
16: 12 = 1 (4 in remainder)
4: 4 = 1 (0 remainder)
1+4+0=5
5+5=10
10+7=17
17: 7 = 2 (3 in the remainder)
The number 3 corresponds to Tuesday, therefore June 7, 2016 is Tuesday.
