And you all thought I was bad with the birthday math!

Fascinating!



Just goes to show that math will always totally rock!  And birthday math will always rock harder!

And today, I am 51

Or, as I have taken to saying, I have completed 51 revolutions around the sun.  I guess this could also be looked at as the start of my 52nd revolution around the sun.  Come with me.  It is your destiny.

Fifty-one is an odd number.  It's divisible by three, which is cool.  Numbers that divide by three are my favorites.  Yes, I said that.  Actually my real favorite numbers are ones with six or more digits when they are found in my checking account.  Since that never happens, I'll stick with numbers divisible by three.

Do you all know the easy way to tell if 3 will go into a given number?  Add the digits of the number up.  If the sum is divisible by three, then the original number is. 

5 + 1 = 6

Six is divisible by three, so 51 is divisible by three.

If you can't tell if the sum is divisible by three, keep adding the digits together until you come to a sun that you can tell.

578,424,372

5 + 7 + 8 + 4 + 2 + 4 + 3 + 7 + 2 = 42  

Not sure what you've got?  Keep going!

4 + 2 = 6

Six is divisible by three, so 578,424,372 is too.  And also 42!  Isn't it cool?

When I was a kid I used to entertain myself on car trips by seeing if the numbers on billboards, license plates, etc were divisible by three.  I still do it sometimes when I'm bored.  Once a nerd, always a nerd.

Finally, the source of my fascination with threes.  I was a kid in the 70's after all.  The part when they start counting by threes  gets me every time.



Happy Birthday to me!  (I don't think "51st Revolution Around the Sun Completion Day" works in the song.  Someone will have to do something about that.)

Fun Finds: Math Scale!

As a math instructor, I totally love this baby!  It's a vintage math teaching tool set up like a little scale.

Sweet 1950's kid graphics always make stuff more fun!

"Add-A-Count"  I love it!

Here you can see the base of the scale is marked off as "Right" or "Wrong."  That's not a moral judgement, mind you, but speaks to the accuracy of your math.

Dare you face the judgement of the Add-A-Count???

Only when there is balance is there also right.

You can put as many numbers as you want on either side of the scale to perform your calculations, but there's a catch!

Each letter is weighted a little differently, and the scale will only balance when the total on each side is the same.

Let's start with a seven.

TILT!

Now let's add a four.

Now a two.  Still not balanced.

But, if I add a one, then everything is hunky-dory!

7 = 4 +2 +1

That is right.  

Balance Restored!

The scale has spoken!

Let all heed the Add-A-Count!