Does 2k4 Mean 2004 or 2400?
Date: 01/10/2004 at 22:30:09 From: Sean Subject: Is 2k4 2004 or 2400? On internet communities it is common to reduce figures using K as a shortcut, for example 2k instead of 2000. I was always under the impression that a number after the K, such as 2k4, meant 2400 and that to get 2004 in this system you'd need to write 2k004. However, it is common for 2k4 to stand for 2004 instead. Which is correct? Is 2K4 2004 or 2400?
Date: 01/11/2004 at 22:55:29 From: Doctor Peterson Subject: Re: Is 2k4 2004 or 2400? Hi, Sean. Interesting question! Here's my take on it. This appears to be a recently invented notation, so the community that invented it and uses it gets to define it! If they use 2k4 for 2004 (as I have seen that they do), then that's what it means. Mathematically, the closest standard notation to this is the metric system, where 2 km means 2 kilometers; people apply that without a unit and use "2k" to mean "2 thousand". But there is nothing in that system to allow putting a number after the "k"; if it meant anything, it would mean "2000 4's", or 8000! I know of no notation in which concatenation implies addition rather than multiplication. For that reason, I'd rather see "2k+4" used instead of 2k4; but since there is no other way to take it, there's nothing really bad about using the latter notation. In any case, I don't see that 2k4 would mean 2400 (2.4k), or that adding extra zeros would make it mean 2004. I do know that in some cultures a unit can be used as the decimal point, at least in speaking if not in writing, as for example one might read "$2.04" as "two dollars four"; in that case, what follows the unit ("four") is not necessarily the next decimal place, but the next standard unit (in this case cents). Taking that approach, 2k4 would probably still mean "2 thousand [and] four [units]". So I see no problem from that quarter. Because this piqued my curiousity, I did a little research and found that, although I wasn't aware of it, electrical engineers do use 2k4 for 2.4k (in certain specific contexts) for practical reasons: http://www.ibiblio.org/obp/electricCircuits/DC/DC_4.html In recent years a new style of metric notation for electric quantities has emerged which seeks to avoid the use of the decimal point. Since decimal points (".") are easily misread and/or "lost" due to poor print quality, quantities such as 4.7 k may be mistaken for 47 k. The new notation replaces the decimal point with the metric prefix character, so that "4.7 k" is printed instead as "4k7". Our last figure from the prior example, "0.267 m", would be expressed in the new notation as "0m267". More details are given here: http://www.nutsvolts.com/PDF_Files/circuit.pdf ... Matters reached a historic peak in 1975 when the British Standards Institute (BSI) published — after a very long period of study and consultation — a list of recommendations concerning this subject. ... [T]hose relating to an international system of electronic component value notation were excellent, and were soon adopted by most of the world’s industrial nations, with the notable exception of the USA. This new notation system was, in effect, an improved and streamlined version of the existing SI-based system, and was thus quite easy to learn. When its basic form was first specified, it was required to be designed as a simple easily printed code that indicates an electronic component’s value clearly, briefly, without ambiguity, and with a minimum loss of clarity if poorly printed. This last requirement immediately ruled out the use of decimal points in the new code system, and the requirement for brevity called for (1) the elimination of all superfluous information from the code, and (2) for sensible compression of the remaining data. Regarding point (1) in the ‘brevity’ requirement, note that in circuit diagrams, when indicating the value of a symbolic resistor, capacitor, or inductor, it is self-evident that the component’s value is expressed in basic units of ohms, Farads, or Henrys, and the new code’s design specification thus demanded the elimination of this superfluous ‘postscript’ data from the printed code when used in circuit diagrams (but not necessarily in normal printed text). Regarding point (2) in the ‘brevity’ requirement, this was to be aided by using a fixed three decade spacing between the decimal ‘multiplier’ units used to indicate a component’s value. ... Decimal points sometimes become so severely degraded during the printing process that they cease to have a final practical value. ... The important thing to note from the above is that decimal points often become severely degraded during the printing process and, in their 1975 report, the BSI recommended that, for component/parameter value notation purposes, the decimal point should no longer be used and should be replaced by the basic component/parameter multiplier symbol (such as V, k, n, µ, etc.) applicable to that value. Thus, in this system, values such as 4.7V, 4.7kW, and 4700pF (= 0.0047µF or 4.7nF) become 4V7, 4k7, and 4n7. There are four major differences between the International and US Customary notation systems, and two of these are illustrated in Figure 9, which shows the multiplier symbols that are used in the International system; compare this diagram with that of Figure 8, and note that the International system uses the symbol R to indicate basic resistance units, and uses the symbol n to indicate ‘thousandths of a µF’ capacitance units. Of the remaining two differences, one is that — in circuit diagrams — the International system does not use basic component ‘type’ symbols (such as W, F, or L) as component postscript notations, and the other is that the International system used the component’s multiplier symbol in place of a decimal point in the actual component-value notation. This is only now becoming common in America, which explains why I wasn't familiar with it despite past experience in electronics. But the main point is that this system is not a standard practice in SI, but only something used in the electronics industry; it can't be expected to influence popular usage, and thus has no real bearing on the "2k4" issue, except to add more weight to the fact that using 2k4 for 2004 is non-standard and can only be considered an idiom, not a natural extension of any ordinary usage. This page deprecates the usage for the reason you give: http://www.mit.edu/people/klund/2k2.html In engineering, the construction "2k4" is often used as an abbreviation for "2.4k", meaning "two thousand, four hundred" (2400). This construction replaces the decimal point with an SI exponent abbreviation to save space. Similarly, "2M2" would be an abbreviation for the number 2,200,000 and "3m3" would be an abbreviation for the fraction 0.0033. Unfortunately, some people use "2k4" as an abbreviation for the current year, 2004. This usage is dead wrong. We all got excited when we figured out that we could abbreviate the year 2000 as "Y2k," but it's over now. There is no longer a short and clever abbreviation for the current year: we're just going to have to write out all four digits. "2k4" and "2k5" won't be here for centuries. Some people argue that "2k4" can be pronounced "two thousand four," so it is an acceptable written abbreviation. Eye sea they're point, butt its still knot correct. Please, help stamp out the incorrect use of 2k4! And don't start using 2k5. Think of the children. I don't feel quite so strongly about it, but I have to agree: if this usage continues for very long, it will become very silly. Once we get to 2k10, hopefully people will realize they are not saving anything by replacing a 0 with a k! Until then, we just have to warn them that they will not always be understood when they use it. But then, that is part of the charm of jargon, and may not dissuade those who like cryptic language! - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
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