School-Safe Puzzle Games

Mark Your Calendars

Something is going to happen on April 5th of next year that hasn’t happened since June of 1987. What is it?

Much Thanks to PuzzleMaster BoboTheBear for submitting this!!

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9 Comments to “Mark Your Calendars”


  1. Shawn | PUZZLE GRANDMASTER | Profile

    My high school graduation? Not again!!!


  2. Shawn | PUZZLE GRANDMASTER | Profile

    1987 was the last year that all 4 digits of the year were different (no repeating numbers).


    June was the last month in 1987 in which, when you converted the month and day to digits (6/2/1987) you could product all 5 numbers as non-repeating. June 5 was the last day for which this held true (omitting leading zeroes).


    Each year since 1987 has contained repeating digits, until 2013, and on 4/5/2013, we will once again have an extremely non-repetitive day.
    And 4/6, and 4/7, and 4/8, and 4/9…..


    4/5/2013 is kind of special, because the digits can be re-arranged into an uninterrupted sequence, 0-1-2-3-4-5.


  3. Hex | PUZZLE MASTER | Profile

    5.4.2013: digits 0-5


    x.6.1987: digits 6-9, but what about the 1? Unless x is zero and hence the sequence 6-10


  4. Adam | Profile

    The date (4/5/2013) will not contain any repeating digits.


    The last time this occurred was 6/30/1987.


  5. Shawn | PUZZLE GRANDMASTER | Profile

    Of course Adam is right, 6/30 is a better answer than my 6/5.


    Hex, if it is sequentialism that you crave, use June 20 and let the digits “wrap around.” You will get 6,7,8,9,0,1,2.


  6. Bobo The Bear | PUZZLE MASTER | Profile

    Nicely done, Shawn and Adam, you guys nailed it. And good job to Hex, too, for noting another “special” property that April 5 will have.


  7. esterantonia | Profile

    U.S.A independence day


  8. esterantonia | Profile

    Aaak.. I was wrong. I remember July instead of April.


  9. Bobo The Bear | PUZZLE MASTER | Profile

    Yeay! “No Repeating Digits Day” is today!


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