# Unit 7 Letters in Math: English Letter Indicator

Mathematics often uses letters as variables, identifiers, abbreviations, or functions. A single letter that is not modified by typeform, may be transcribed in UEB, but a letter that is part of a mathematical expression must appear between Nemeth Code switch indicators, and when an entire block of text is presented in Nemeth Code, more extensive rules for the use of letters are required.

*Important Note: The extent to which Nemeth Code switch indicators are used will be determined by the transcriber (see Unit 4). Therefore, Nemeth rules have been listed where UEB transcription may also be appropriate.*

# Uses of the Nemeth Code ELI

Even though Nemeth Code does not use contracted braille, when a single letter or a combination of letters could be misread as a contraction or short form word, an English Letter Indicator (ELI) is placed in front of the letter(s) to distinguish it from a word, abbreviation, or other Nemeth symbol.

*Note: Nemeth Code switch indicators have been included in each example for clarity.*

English Letter Indicator | ⠰ |

There are specific rules for when and when not to use the ELI, and although the ELI’s appearance is the same as the UEB grade 1 indicator, its purpose is to clarify a single letter, and its affect only extends to the following letter.

# Single Letter Rule:

An ELI is required before a single letter that:

* is unmodified and in regular type

* is preceded and followed by a space or punctuation mark

* is not an abbreviation or a word (Note: the letters "a", "A", "I", and "O" can be considered words)

* is not part of a mathematical expression

# Examples:

a, b, c

⠸⠩⠀⠰⠁⠠⠀⠰⠃⠠⠀⠰⠉⠀⠸⠱

find x

⠸⠩⠀⠋⠊⠝⠙⠀⠰⠭⠀⠸⠱

point D

⠸⠩⠀⠏⠕⠊⠝⠞⠀⠰⠠⠙⠀⠸⠱

d)

⠸⠩⠀⠰⠙⠾⠀⠸⠱

The ELI is also required before a lowercase letter combination that contains the same letters as a short form word to clarify its meaning (capitalized short form combinations do not need an ELI).

# Examples:

angle acr

⠸⠩⠀⠁⠝⠛⠇⠑⠀⠰⠁⠉⠗⠀⠸⠱

segment ac

⠸⠩⠀⠎⠑⠛⠍⠑⠝⠞⠀⠰⠁⠉⠀⠸⠱

triangle dcl

⠸⠩⠀⠞⠗⠊⠁⠝⠛⠇⠑⠀⠰⠙⠉⠇⠀⠸⠱

Compare lines ab, bc, and cd.

⠠⠉⠕⠍⠏⠜⠑⠀⠇⠔⠑⠎⠀⠸⠩⠀⠰⠁⠃⠠⠀⠃⠉⠠⠀⠠⠄⠯⠀⠰⠉⠙⠀⠸⠱⠲

# Non-Use of the Nemeth Code ELI

The following rules outline when the ELI is not required in Nemeth transcriptions of mathematical context.

*Note: The remainder of the lesson is written in Nemeth Code without the use of code switch indicators and uncontracted braille is used where needed.*

# Non-Use of ELI #1:

Any letter that is part of a mathematical expression or equation does not require an ELI. Although variables are typically written in italic typeface, this typeform is disregarded in braille.

# Examples:

x – 2

⠭⠤⠆

b + 5

⠃⠬⠢

t + x – 5

⠞⠬⠭⠤⠢

$\frac{x}{y}$

⠹⠭⠌⠽⠼

# Non-Use of ELI #2:

The letter(s) is preceded or followed by a sign of comparison (clarifying it as a mathematical expression).

# Examples:

q = r

⠟⠀⠨⠅⠀⠗

D = 10

⠠⠙⠀⠨⠅⠀⠼⠂⠴

x+y = z

⠭⠬⠽⠀⠨⠅⠀⠵

a+b = b+a

⠁⠬⠃⠀⠨⠅⠀⠃⠬⠁

ab = cd

⠁⠃⠀⠨⠅⠀⠉⠙

$r\, = \,\frac{d}{t}$

⠗⠀⠨⠅⠀⠹⠙⠌⠞⠼

< h

⠐⠅⠀⠓

12 > g

⠼⠂⠆⠀⠨⠂⠀⠛

# Non-Use of ELI #3:

The letter or letters occur in an unspaced sequence of terms within the Nemeth Code (therefore, already clarified as uncontracted braille).

# Example:

2a+2b+2c

⠼⠆⠁⠬⠆⠃⠬⠆⠉

y = mx+b

⠽⠀⠨⠅⠀⠍⠭⠬⠃

3xyz

⠼⠒⠭⠽⠵

p(1+m)(4-n)

⠏⠷⠂⠬⠍⠾⠷⠲⠤⠝⠾

$\frac{1}{x} = \frac{1}{y} + \frac{1}{z}$

⠠⠎⠕⠇⠧⠑⠀⠹⠂⠌⠭⠼⠀⠨⠅⠀⠹⠂⠌⠽⠼⠬⠹⠂⠌⠵⠼⠀⠋⠕⠗⠀⠰⠵

# Non-Use of ELI #4:

1. The letter(s) is entirely enclosed in a pair of grouping symbols.

# Example:

(b)

⠷⠃⠾

{C}

⠨⠷⠠⠉⠨⠾

* Notice that the capital letter indicator is also enclosed inside the grouping symbols.

[cd]

⠨⠷⠉⠙⠨⠾

5(ab)

⠼⠢⠷⠁⠃⠾

# Punctuation and Capitalization

Letters in Nemeth are considered math symbols and, therefore, are punctuated according to Nemeth rules for punctuation indicator (PI).

# Example:

a. b. c.

⠰⠁⠸⠲⠀⠰⠃⠸⠲⠀⠰⠉⠸⠲

Solve "b" if 2(b+12) = 72

⠠⠎⠕⠇⠧⠑⠀⠦⠰⠃⠸⠴⠀⠊⠋⠀⠼⠆⠷⠃⠬⠂⠆⠾⠀⠨⠅⠀⠼⠶⠆

$\frac{y}{z}}=x{;}x=$⠹⠽⠌⠵⠼⠀⠨⠅⠀⠭⠸⠆⠀⠭⠀⠨⠅

# Capitalization of Letter Sequence and Non-Use of ELI

Remember that letters are capitalized individually in Nemeth Code, therefore, a capitalized letter sequence does not require an ELI because it cannot be misread as a short form word.

# Example:

angle ABC

⠁⠝⠛⠇⠑⠀⠠⠁⠠⠃⠠⠉

line CD

⠇⠊⠝⠑⠀⠠⠉⠠⠙

Line GD

⠠⠇⠊⠝⠑⠀⠠⠛⠠⠙