Numerator, Denominator: Etymologies
Date: 03/25/2002 at 20:01:02 From: Faith Baker Subject: Numerators and denominators Why are the parts of a fraction called the numerator and the denominator? Thanks for the help!
Date: 03/26/2002 at 02:51:14 From: Doctor Sarah Subject: Re: Numerators and denominators Hi Faith - thanks for writing to Dr. Math. In a fraction, the numerator tells you the number of things you have, and the denominator tells you the kind of thing you're dealing with. From Steven Schwartzman's _The Words of Mathematics_: numerator the first element is from Latin numeratus, past participle, or numerare "to number." The more basic word is the Latin masculine noun numerus "number"... A numerator is literally "a numberer." In arithmetic, the numerator of a fraction gives the number of parts being considered, where each part is an equal fraction of the whole. Since the numerator tells you how many parts you have, when you add fractions you add only numerators, never denominators... denominator from Latin de and nomen, "name," cognate to the English word with the same meaning... In arithmetic the denominator of a fraction names the kind of thing you're dealing with. In the fraction 3/5, for example, you have three fifths, just the way you could have three sheep or three apples or three of any other thing... Since the denominator names the sort of a thing you're dealing with, you must have a common denominator when you add fractions; otherwise it's like trying to add sheep and apples... - Doctor Sarah, The Math Forum http://mathforum.org/dr.math/
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