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Calculation Breakdown:
Day of Week (DOW) Calculation (1753–2799)
CREATED BY JACKIE DANDER Copyright 2026
Note: After February 29, 2800 there will be two calendars in use, the Revised Julian and the Gregorian. So, we stop at 2799. And before 1753, the USA and world used the Julian calendar, so we stop at 1753.
Jackie Dander came up with this method as the simplest memorization method for performing Day of Week tricks standing in front of audiences. It is just figuring out 6 numbers.
He thinks you can master the memorization in a few days if you have talent for memorizing lists.
For Jackie, at age 78, he thinks it is a better brain exercise than crossword puzzles. He has honed his Day of Week skills to average 30 seconds. See if you can beat him!
And smile when an audience member gives you an easy date, such as July 4, 2400. As you will find out, that date can be resolved in 3 seconds as Tuesday.
Look at the app and there are many dates like that. Maybe quit during a presentation if you get an easy one like that.
Bonus golly-whacker Hint: As you will find out, the last step is to "modulo 7" the sum but the super hint is that you can modulo-7 along the way anytime your addition gets to 7, 14, 21, 28, 35, etc, etc.
That means if your date is December 26, then N1 + N2 = 28 and that's zero after modulo 7 so note the zero and go on to N3-4-5-6 to finish calculations.
What days of the week are going to impact you the most, going forward?
Yes, this year, next year and maybe the year that follows. So, as I write this that would be 2026, 2027 and 2028. So, I memorize N3 + N4 + N5 + N6 for those years.
And:
2026 totals for N3/4/5/6 = 6
2027 totals for N3/4/5/6 = 0
2028 totals for N3/4/5/6 = 2
Wow!
That speeds things up and is very useful. If your birthday is September 6th, then you know that your birthday falls on Sunday this year, Monday next year, and Wednesday in 2028. (N1 = 2, N2 + 6, so sum so far is 8. Then add 8 to the three memorized numbers above, and modulo the sum by 7.)
Because 2027 is around the corner, take advantage of N3+N4+N5+N6 = 0 for 2027. So, for any date during 2027, the memory skill to determine the day of the week for any day is only to add N1 + N2 and use that sum.
He thinks you can master the memorization in a few days if you have talent for memorizing lists.
For Jackie, at age 78, he thinks it is a better brain exercise than crossword puzzles. He has honed his Day of Week skills to average 30 seconds. See if you can beat him!
And smile when an audience member gives you an easy date, such as July 4, 2400. As you will find out, that date can be resolved in 3 seconds as Tuesday.
Look at the app and there are many dates like that. Maybe quit during a presentation if you get an easy one like that.
Bonus golly-whacker Hint: As you will find out, the last step is to "modulo 7" the sum but the super hint is that you can modulo-7 along the way anytime your addition gets to 7, 14, 21, 28, 35, etc, etc.
That means if your date is December 26, then N1 + N2 = 28 and that's zero after modulo 7 so note the zero and go on to N3-4-5-6 to finish calculations.
What days of the week are going to impact you the most, going forward?
Yes, this year, next year and maybe the year that follows. So, as I write this that would be 2026, 2027 and 2028. So, I memorize N3 + N4 + N5 + N6 for those years.
And:
2026 totals for N3/4/5/6 = 6
2027 totals for N3/4/5/6 = 0
2028 totals for N3/4/5/6 = 2
Wow!
That speeds things up and is very useful. If your birthday is September 6th, then you know that your birthday falls on Sunday this year, Monday next year, and Wednesday in 2028. (N1 = 2, N2 + 6, so sum so far is 8. Then add 8 to the three memorized numbers above, and modulo the sum by 7.)
Because 2027 is around the corner, take advantage of N3+N4+N5+N6 = 0 for 2027. So, for any date during 2027, the memory skill to determine the day of the week for any day is only to add N1 + N2 and use that sum.
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