Sender: Linda

Could you tell me the name for the bar in a division problem. Not the line with dots on either side but the line that divides the two numbers? My name is Linda and I am asking for my niece who is in 8th grade.

Thank you. Linda

Hi Linda:

For many centuries the standard way to write a quotient has been to put the dividend over the divisor, separating them by a horizontal line. That line seems to be called simply a "horizontal line" or a "horizontal bar." (I saw this terminology in both the OXFORD ENGLISH DICTIONARY and in A HISTORY OF MATHEMATICAL NOTATIONS. The latter is an authoritative book written in 1928 by Florian Cajori.) If you wish, we give you permission to call it "the dividing line," which seems quite appropriate.

Printers never liked the notation because it wasted both time (it is difficult to set) and paper (it requires a greater line width). Many different replacements were proposed. During the last century British mathematicians began to favor what they called the "solidus notation" a/b for "a divided by b". SOLIDUS came from the name of a Roman coin which evolved into the British shilling. The solidus (/) was originally written as a long s (still used today in our integral symbol) and used to separate shillings from pence: so that 12/6 would mean 12 shillings and six pence. Since the name solidus was well established by the time the mathematicians began using it, they just took up that name. One can also find "/" called a "slant line", a "slash" or a "virgule". (The last came about because during the middle ages it was an alternative for a comma; people outside mathematics tend to favor the name virgule.)


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