144. The Ones Have It

Friend Linda Lewis sent this interesting note:

“This year we will experience 4 unusual dates …. 1/1/11, 1/11/11, 11/1/11, 11/11/11.


Now go figure this out. Take the last 2 digits of the year you were born plus the age you will be THIS year and it WILL EQUAL 111.”

Thanks, Linda!  That’s cool.

I wish I knew why it works.  If you know the magic behind it, please explain it in a comment.

The number 11 is a prime number – not divisible by anything except itself or the number 1.  That’s all I know about this odd number except the easy way you can multiply with it. For doing it here’s a handy little instruction I snapped off the internet.

The 11 Rule

You likely know the 10 rule (to multiply by 10, just add a 0 behind the number) but do you know the 11 rule? It is as easy! You should be able to do this one in you head for any two digit number. Practice it on paper first!

To multiply any two digit number by 11:

  • For this example we will use 54.
  • Separate the two digits in your mind (5__4).
  • Notice the hole between them!
  • Add the 5 and the 4 together (5+4=9)
  • Put the resulting 9 in the hole 594. That’s it! 11 x 54=594

The only thing tricky to remember is that if the result of the addition is greater than 9, you only put the “ones” digit in the hole and carry the “tens” digit from the addition. For example 11 x 57 … 5__7 … 5+7=12 … put the 2 in the hole and add the 1 from the 12 to the 5 in to get 6 for a result of 627 … 11 x 57 = 627
Practice it on paper first!

Finally, while you’re manipulating elevens, how about a little card trick? I was looking for one that involves the number 11, but this one looked like fun.

Before you watch the video tutorial, have a deck of cards handy.  During the steps, you’ll use – not 11 – but 9 of them.


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3 Responses to 144. The Ones Have It

  1. Linda Lewis says:

    Isn’t knowing the trick like asking for the score in a symphony or secret ingredients to a family recipe? Check your email. :o)
    Now figuring out why the card trick works is another thing…

  2. Gretchen Covey says:

    Amazing, baffling. Blessing on the great minds that figures these things out! God’s creativity is endless.

  3. Octo-woman says:

    Brother-in-law Don Ford found a friend who unlocked the system. Here’s their conversation: .
    Don Ford” wrote:
    Thanks Dave but wh ere did you find it?….Don

    From: “Dave Cole”
    To: “Don Ford” Sent: Wednesday, February 16, 2011 4:58 PM
    Subject: Re: [New post] 144. The Ones Have It

    Hi Don… I do… I of course cheated and looked it up! Here is the answer:

    If you were born between 1900 and 1999, then:
    your age on your birthday this year will be 2011 – (1900 + d),
    where d is given by the last two digits of the year you were born.
    Since 2011 – (1900 + d) = (2011 – 1900) – d, when you add your age
    this year to the last two digits of the year you were born the result is (2011 – 1900) – d + d = 2011 – 1900 = 111.
    I knew this, but was unable to articulate it correctly, so I looked for a better articulation of the rules…
    Hope this helps


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