Base 5 Option on newer Sharp Calculators

[Shura]

Hi,

Recently I have noticed that Sharp have added Base-5 to their newer model calculators. e.g. The EL-531WBBK

http://www.sharpusa.com/products/Mod...8,1373,00.html

Not all the calculators with this option have it listed in their manuals, but the

http://www.sharpusa.com/files/cal_man_EL531_509.pdf

manual has a very clear entry. Unfortunately it is 3Mb, which might be a bit much for those on dial-up. You cannot clearly see option on the calculator pictures even if you zoom in.

Anyway

Base 2 – Binary, and Base 16 - Hexadecimal I can understand as these are used in computing.

Base 8 - Octal I can understand as used to be used a lot more with computers, that it is today.

But does anyone know why Base 5 has been added? I have searched the web and been unable to find any references. They refer to it as Pental (But since theirs are the only calculators with this on that I can find, I don't know it this is a standard name, or if Sharp have just made it up)

You can of course choose any base, we could have Base 9, Base 11 etc. But does anyone know why Sharp would have gone to the trouble of actually adding a Base 5 option to their calculators. I assume that they have only done it because there is some specific use.

Does anyone know what this is?

- Shura.