[Blindmath] what's the braille notation for recurringdecimal point in

Susan Jolly easjolly at ix.netcom.com
Fri Aug 5 18:37:39 UTC 2011


I think there is a confusion about what is being asked.

There is a print symbol that visually looks like three dots or three decimal 
points or three periods arranged in a horizontal row.  The correct name for 
this symbol is ellipsis.  This is represented in Nemeth braille by a 
sequence of three dot-3 braille cells. In print it is sometimes represented 
by three separate periods and sometimes by a single print character which 
resembles three separate periods close to each other.

The ellipsis is often used in math to show that something has been left out 
where what has been left out is either obvious from context or unimportant.

There is also a mathematical construct known as a recurring or repeating 
decimal, not decimal point.  This refers to a repeated number or number 
sequence that occurs somewhere after a decimal point and repeats 
indefinitely.  Thus in the number 5.4333 the 333 might be a recurring 
decimal.  Print math uses two methods to indicate that the 333 repeats 
indefinitely.  One method is to place an ellipsis after the number. 
However, the preferred method to indicate the repitition is to place a bar 
over the number or sequence that repeats.  In this example you would write 
5.43 with a bar over the three.

In the number 5.4323232 the 32 might be a recurring decimal.  If so, you 
would write 5.432 with a single bar over the digits 32.

If a single digit repeats indefinitely, it is indicated in Nemeth by 
following it with the dots-156 cell  that represents an over bar.

If two or more digits repeat indefinitely, it is indicated in Nemeth using 
the modifier notation.  (This notation is used for print underscripts and 
overscripts.)  In this case a dot-5 is placed before the first digit of the 
sequence and then a three-cell modifier is placed after the last digit in 
the sequence.  The first cell of the modifier, dots-126, indicates that the 
next symbol is an over script.  The second cell, dots-156, is the horizontal 
bar.  The third cell, dots-12456, is the modification terminator.

HTH,
SusanJ 





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