The Museum of HP Calculators

HP Forum Archive 14

 PentalMessage #1 Posted by John Limpert on 11 Mar 2005, 1:04 p.m. While looking at the documentation for a Casio calculator, I noticed that it had base conversion support for pental. Has anyone seen that feature in other calculators? What might it be used for?

 Re: PentalMessage #2 Posted by Crawl on 11 Mar 2005, 4:56 p.m.,in response to message #1 by John Limpert Some Sharps (like the 506W) have that feature. I've assumed it's mostly fluff.

 Re: PentalMessage #3 Posted by Ronald on 11 Mar 2005, 5:09 p.m.,in response to message #2 by Crawl Hi, Maybe I have become rusty in my grey cells, but what is a "pental" Thanks Ronald

 Re: PentalMessage #4 Posted by John Smitherman on 11 Mar 2005, 6:19 p.m.,in response to message #3 by Ronald I assume that pental means base 5 whereby decimal 5 would be represented by 10 and decimal 10 would be 20. I've never seen a computer that uses base 5. I've worked on several that use base 2, base 8 and base 16. John

 Re: PentalMessage #5 Posted by Mark Hardman on 11 Mar 2005, 9:23 p.m.,in response to message #4 by John Smitherman I think the most common use of the pental numbering system is by prisoners in institutions of incarceration. Prisoners mark the passage of days by marking on the wall. Days are counted using four vertical strokes for the first four days. The fifth day is marked with a diagonal line across the group of four. After that, a new group of five is started. Here's an example from a modern pentaltentiary. ;) Mark Hardman Houston, TX Edited: 11 Mar 2005, 9:31 p.m.

 Re: PentalMessage #6 Posted by John Limpert on 12 Mar 2005, 12:00 a.m.,in response to message #5 by Mark Hardman Actually, that's a unary numeral system.

 Re: PentalMessage #7 Posted by Veli-Pekka Nousiainen on 12 Mar 2005, 12:55 a.m.,in response to message #5 by Mark Hardman Is it Hard, man, to Mark the walls? (-; [VPN]

 Re: PentalMessage #8 Posted by Monte Dalrymple on 12 Mar 2005, 11:56 a.m.,in response to message #5 by Mark Hardman Isn't the abacus a base-5 machine?

 Re: PentalMessage #9 Posted by Vieira, Luiz C. (Brazil) on 12 Mar 2005, 6:19 a.m.,in response to message #3 by Ronald Hi; based on what I see and teach, the 'number' that describes a 'base number' expresses the quantity that cannot be represented in the 'base number' with a single algarism. You see, octal, base eight, uses eight algarisms and the last one is seven. The decimal quantity 'eight' is represented as '108' or '10o'. Pental refers to a base number with five algarisms, being them 0, 1, 2, 3 and 4. The decimal quantity 'five' should be expressed '105'. Intriguing! Cheers. Luiz (Brazil)

 Re: PentalMessage #10 Posted by Mike Sebastian on 12 Mar 2005, 1:01 a.m.,in response to message #1 by John Limpert Which Casio calculator? The latest Sharps, which include the EL-506W, are the first calculators I've seen with base 5.

 Re: PentalMessage #11 Posted by John Limpert on 12 Mar 2005, 6:59 a.m.,in response to message #10 by Mike Sebastian You're right. It was a Sharp EL-506WB. I had it confused with another calculator.

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