| Instructions |
Example:
November 12, 2070 |
Step 1: Determine the code for the century:
| Century: | 1800's | 1900's | 2000's | 2100's |
| Code # | 2 | 0 | 6 | 4 |
|
Century = 2000's
The code for 2000's is 6
Shortcut: Use -1 instead of 6 for 2000's to make the arithmetic easier.
Total = 6
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Step 2: Determine the code for the year:
| Year: | 00 | 04 | 08 | 12 | 16 | 20 | 24 |
| 28 | 32 | 36 | 40 | 44 | 48 | 52 |
| 56 | 60 | 64 | 68 | 72 | 76 | 80 |
| 84 | 88 | 92 | 96 | |
| Code # | 1 | 6 | 4 | 2 | 0 | 5 | 3 |
|
Year = 70
68 is 2, so 69 is 3 and 70 is 4!
Total = 10 (6 + 4)
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Step 3: Determine month code:
Jan = 6 | Feb = 2 | Mar = 2 | Apr = 5 |
May = 0 | Jun = 3 | Jul = 5 | Aug = 1 |
Sep = 4 | Oct = 6 | Nov = 2 | Dec = 4 |
|
Month = November
November = 2
Total = 12 (6 + 4 + 2)
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Step 4: Determine date code:
| Date: | | 1 | 2 | 3 | 4 | 5 | 6 |
| 7 | 8 | 9 | 10 | 11 | 12 | 13 |
| 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 21 | 22 | 23 | 24 | 25 | 26 | 27 |
| 28 | 29 | 30 | 31 | |
| Code # | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
|---|
|
Date = 12
The code for date:12 is 5.
Total = 17(6 + 4 + 2 + 5)
Shortcut #1: Subtract 7, 14, 21 or 28, from the date to find code, dates less than 7 are
already equal to the code.
Example:
Nov 12: 12 - 7 = 5.
Example:
Nov 26: 26 - 21 = 5
Shortcut #2: Simply add the date to the total. Example: Nov 12: Code=12, Total = 24 (6 + 4 + 2 + 12).
Flashcards
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Step 5: Determine day-of-week from total
Divide the total from Step 3 by seven, the remainder
giving the day-of-week:
| Day-of-week: | Sun | Mon | Tue | Wed | Thu | Fri | Sat |
| Remainder: | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
|---|
|
Total = 17 (Century=6, Year=4, Month=2, Date=5)
17 divided by 7 is:
2 remainder 3
3 = Wednesday
Shortcut: Instead of dividing, just subtract 7, 14, 21, 28, or 35, etc. (multiples of 7)
until you have a number 0 to 6. For example, 17 - 14 = 3. If the total was 30, then 30 - 28 = 2 = Tuesday.
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Step 6: Don't forget leap-year!
Subtract 1 at any point in the process only if the year
is a leap year, and the month is January or February!
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2070 is not a leap year.
Shortcut #1: The year is a leap year if it is found in the table in step 1. (68 and 72 are leap years, but 70 is not)
Shortcut #2: A year is a leap year if it is evenly divisible by 4.
Shortcut #3: As a last step, you can simply take the day before (if the year is a leap year, and the month is Jan. or Feb.)
Click here
for the rare exceptions to the above shortcuts.
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