Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: sexagesimal math with the "40 method"
    From: Dan Allen
    Date: 2003 Feb 14, 12:39 -0800

    On Friday, February 14, 2003, at 12:21 PM, Paul Hirose wrote:
    
    > In an old surveying publication I saw a nice trick for adding
    > sexagesimal numbers on an electromechanical calculating machine. If
    > the minutes or seconds summed to 60 or more you added 40 to the part
    > that "rolled over".
    
    This appears to be generalizable to any base by simply subtracting the
    base from 100 to determine the "magic factor" that is added back in.
    
    Seconds or minutes = base 60, so 100 - 60 = 40
    Hours = base 24, so 100 - 24 = 76
    
    Neat!
    
    Dan
    
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site