8.2 Working with Real Numbers: Plus/Minus Sign and the Not Equals Sign

The Plus or Minus Sign

The braille symbol for the plus or minus sign, dots three four six dots three six, is comprised of the plus sign followed by the minus sign. The print equivalent to this symbol is the plus sign above the minus sign, in a vertical arrangement. Although rarely used, the minus or plus symbol, dots three six dots three four six, has the same meaning as the plus or minus sign. Students should remember that the use of the plus or minus sign indicates that there are actually two answers.

Occasionally, the two symbols for plus and minus are joined horizontally in print. In braille, the multipurpose indicator, dot five, is placed between the two signs of operation. This serves to indicate that the two symbols are printed horizontally and not vertically. Following are the possible combinations of these signs:

plus followed by minus, dots three four six dot five dots three six
minus followed by plus, dots three six dot five dots three four six
plus followed by plus, dots three four six dot five dots three four six
minus followed by minus, dots three six dot five dots three six

Variations of the equals sign

Signs of comparison can be used together and are sometimes shown in print as combined in two different ways. One way is to overlay one symbol on top of another, over-striking. A second way is to join them vertically with one symbol above another. In braille, the combination is displayed horizontally. When signs of comparison are combined with other signs of comparison, do not place a space between them.

Signs of comparison can also be negated, representing the concept, "not." In print, the negation is represented by the use of a vertical line or left or right diagonal slash across the sign of comparison. In braille, the sign of comparison is negated by preceding the symbol with dots three four. The negation sign must be the first symbol following the space which precedes the sign of comparison, and should be un-spaced from its companion sign. Because a space is required before and after a sign of comparison, the oblique slash is not mistaken as a sign of operation.

Not equal sign

The symbol for not equal, dots three four dots four six dots one three, is used in a similar manner to the sign for equals. Its meaning, however, is simply that the amounts on either side of it are not identical. The not equal sign follows the rules for signs of comparison.

A Question Mark Above the Equal

In print, a question mark is sometimes written above the equal. Its meaning is to question whether the amounts on either side of the equal are indeed identical. The symbol for a question mark over an equal is dot five dots four six dots one three dots one two six dots four five six dots two three six dots one two four five six. Thus, it is the multipurpose indicator, dot five, followed by the equals sign, the raised above symbol, the punctuation indicator, the question mark, and finally the termination indicator.

Example 1

plus or minus thirty one

Example 2

seven plus or minus three

Example 3

six minus or plus four

Example 4

negative five plus followed by negative two

Example 5

seven minus followed by minus three

Example 6

three plus five is not equal to fifteen

Example 7

three plus five question mark above equal fifteen

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