Background: last weekend my 12-year-old son wanted to know what day of the week a particular past date fell on. I told him there was a (reasonably) easy way to figure it out, based on a trick I had read years ago in Omni magazine. He and my wife found it interesting and clever, but a search of the Internet turned up no trace of it. Hence (warning: non-sequitor approaching), I decided to turn it into a Sporcle game, to keep the trick alive and also because I'm on a business trip and bored out of my mind.
There's obviously not a whole lot to the "game", except to say that it's accurate for any date from 1900 through 2015. Far more interesting is learning how you can do this simple calculation in your head and amaze your friends, provided that they amaze easily. Say you were born on July 4, 1976...
Step 1: Take the two-digit year. (76)
Step 2: Add to this number the two-digit year divided by 4, discarding any remainder. (76/4=19.0 --> 76+19=95)
Step 3: Add the key month value, discussed below. (July=0 --> 95+0=95)
Step 4: Add the day of the month. (95+4=99)
Step 5: If the date is in January or February of a leap year, subtract 1. (Still 99)
Step 6: If the date is in the 2000s, subract 1. If it's in the 1800s, add 2. If it's in the 1900s, do nothing. (Still 99)
Now divide by 7 and take the remainder. (99/7=14 rem 1.) The first day of the week (at least here in North America) is Sunday, and that's your answer. 2=Monday, 3=Tuesday, etc.; 7=0=Saturday.
More to come.... |
German: Days
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