I just published on the App Store the Kaktovik Calculator app I've been working upon for over a year.  Looking back it seems like I wasted lots of time and effort on things I could have known - but didn't. 

The app also has its website - www.Kaktovik-Calculator.com.

In my early experience as a mechanical engineer I learned of the other-worldly use of different numerical bases - number systems did not have to be base-10.  This took me by surprise.  How would a culture that used the "non-standard" numerical system attain devices such as protractors, rulers,  calculators, etc.?  Would they mark out the etched inches on a ruler and write in their units?  I remembered how difficult it was in our feeble attempt to switch to the metric system.  Well, that is just the way the world is, I thought.

Have you ever learned a new number base?  Do you know more than one?  Most people will respond - incorrectly - that they only know decimal (base-10) system. 

They are wrong.

Proof:  How many days in a week?  7.   That means weeks are base 7.  And you use them all the time.  How many minutes in an hour?  60.  Right - that is base 60.  We use base-60 for minutes & seconds.  We use base 24 - for hours a day.  And many peoples favorite 365 for days in a birthday.