Using the PAC Mate to Produce Math Expressions in Print

Introduction

With training and use of appropriate equipment, students who are blind can produce print math expressions which can be easily interpreted by their sighted teachers who do not read braille. Without the recommended training and equipment, a student who uses braille must submit written math assignments to a sighted individual who can read Nemeth Code; the sighted person then must produce a print version of the assignment by interlining the braille with handwritten math symbols which can be read by the math teacher. Elimination of the interim step in which a sighted individual interlines braille results in a more efficient, independent method by which the student is able to communicate with mathematics teachers. The strategy described in the following paragraphs requires the use of a PAC Mate.

To use the PAC Mate to produce math symbols in print, create a new file, and select “no” at the prompt, “would you like to make your new file a braille document?” Input information using the computer braille code. That is, use Nemeth Code numbers (in the lower part of the braille cell with no numeric indicator) and computer code punctuation. Indicate uppercase by pressing dot 7 (the back space key) at the same time as you press any uppercase symbol rather than the capital sign (dot 6). The reader is referred to Code for Computer Braille Notation (1987) and Computer Braille Code Made Easy (1998) for additional information regarding the symbols which comprise the computer braille code.

Braille symbols to use in PAC Mate math files are listed in Table 1. These characters will be accurate representations of the print symbols when printed on an inkprint printer. For other mathematical symbols, use the special key combinations listed for the corresponding symbol. For example, follow these steps to print “ten degrees” with the numeral ten and the print symbol for degrees (10°): 1. Create a new braille file as described above; 2. Type the number,10, in Nemeth Code, without the numeric indicator; 3. Press dots 4-5-6-8; the PAC Mate will say, "degree."

Using this method, the print version of some expressions will be somewhat different than the standard print version, but will be quite easy to interpret. For example, to print the math symbols representing the algebraic expression, x squared plus two x minus one equals zero, follow these steps:

1. Braille the letter, x, without a letter sign.
2. Braille the superscript, 2, using the following modifications:
   • we have chosen to use the caret, or up arrow, to indicate that an expression is at the superscript level. This symbol is brailled by pressing dots 4-5-7.
   • Follow that symbol with the superscripted expression. In this example, it is the numeral, 2.
   • To indicate that the superscript portion of the expression has ended and there is a return to the baseline, braille the dot 5, the Nemeth Code baseline indicator. In the computer code, the dot 5 represents the quotation mark.
   • In print, the expression will appear as follows: x^2”. The sighted math teacher should be informed that this expression means x squared.
3. Braille the remainder of the algebraic expression: the plus sign (dots 3-4-6); computer code numeral 2 (dots 2-3); the letter, x (dots 1-3-4-6); the minus sign (dots 3-6); the computer code numeral 1 (dot 2); the equals sign (spacebar, dots 1-2-3-4-5-6, spacebar); and the computer code numeral 0 (dots 3-5-6).
4. When this expression is printed, it appears as follows: x^2”+2x-1 = 0.

To produce the more complex mathematical expressions found in calculus, we recommend the methods used to input math expressions in computer math programs such as Mathematica (http://www.wolfram.com/) which are, by necessity, limited to symbols on the baseline. Symbols such as the integral, which require more than one linespace in print, are represented by alternative symbols in order to maintain a one-line, horizontal format which can be inserted into a document using symbols on the standard computer keyboard. These expressions are easily read by sighted math teachers who are familiar with these programs. Following are examples of an integral, a summation, and a limit, written in a comprehensible fashion.

The integral from zero to one of v of x with respect to x equals f of one minus f of zero is written as the following using a PAC Mate: Int[0,1]v(x) dx = f(1)-f(0). The left bracket is produced using the dots 2-4-6-7; the right bracket is produced by brailling dots 1-2-4-5-6-7.

An expression indicating summation, the sum from zero to six of 3 to the power i is written as follows using the PAC Mate: Sum[i= 0, 6]3^i. The example of a limit is written in words as follows: the derivative of f of x equals the limit as h goes to zero of f of x plus h minus f of x all over h. Using the PAC Mate, this expression is written in the following manner: f’(x) = lim[h-->0] (f(x+h)-f(x))/h. The arrow is produced by brailling two sets of dots 3-6 followed by the greater than sign, dots 3-4-5.

Table 1: Braille Symbols to Use in PAC Mate Math Files

Symbol Name	Symbol	Dot Configuration	Braille Symbol
ampersand	&	1 2 3 4 6
apostrophe	'	3
backslash	\	1 2 5 6 7
opening brace	{	2 4 6
closing brace	}	1 2 4 5 6
opening bracket	[	2 4 6 7
closing bracket	]	1 2 4 5 6 7
opening parenthesis	(	1 2 3 5 6
closing parenthesis	)	2 3 4 5 6
colon	:	1 5 6
comma	,	6
decimal point	.	4 6
divide (forward slash	/	3 4
dollar sign	$	1 2 4 6
equals	=	1 2 3 4 5 6
exclamation point	!	2 3 4 6
exponent (caret)	^	4 5 7
fraction line	/	3 4
greater than	>	3 4 5
less than	<	1 2 6
minus	-	3 6
multiply (star or asterisk)	*	1 6
number sign	#	3 4 5 6
percent	%	1 4 6
period	.	4 6
plus	+	3 4 6
question mark	?	1 4 5 6
quote	"	5
root sign (tilde)	√	4 5
semicolon	;	5 6
underline	_	4 5 6
vertical line	|	1 2 5 6
cent mark	¢	1 4 5 6 8
plus or minus	±	3 6 7 8
division symbol	÷	3 5 7 8
degrees	°	7 8
squared	²	2 3 5 6 7 8
multiplication cross	x	1 2 3 5 8
accent	`	4
asterisk	*	1 6
at sign	@	4 7
double quote	“	5

References

Braille Authority of North America (2000). Code for computer braille notation. Louisville, KY: American Printing House for the Blind.

Dixon, J. & Gray, C. (1998). Computer braille code made easy. Boston, MA: National Braille Press.