

Subject:
Is .9995 the SAME as 99.95%
Category: Reference, Education and News Asked by: stockzguyga List Price: $5.00 
Posted:
22 Jun 2002 12:25 PDT
Expires: 29 Jun 2002 12:25 PDT Question ID: 31637 
I need some help in clearing up the difference between .9995 and 99.95%. First the background. Coin dealers on eBay and other auction sites advertise US Mint Platinum Eagles (c) and Proofs as .9995. The offical specs., from the US Mint.gov website states that ALL Platinum bullion is 99.95% pure platinum. How did we "magicly" go from .9995, which to me is 10,000 ths., to 99.95%? This is NOT jewelry, these are platinum bullion coins issued by the US Mint and guaranteed for the percentage of their pureness. I emailed one of the auction sellers, and they are claiming that .9995 (no % sign,btw) is the SAME as 99.95%. If this is the case, why does the US Mint put the figure of 99.95% in ALL its' catalogs? Thankz to all the math persons out there. 

Subject:
Re: Is .9995 the SAME as 99.95%
Answered By: justaskscottga on 22 Jun 2002 15:01 PDT Rated: 
Various web sites indicate that, in measuring the purity or fineness of precious metals such as platinum, palladium, and gold  both in coins and in jewelry  the decimal .9995 is the same as the percentage 99.95%, or similarly, the decimal .9999 is the same as the percentage 99.99%. "Feature Article: Metals in Jewelry, Part 1: The 'K' in Gold" All About Jewelry http://www.2globalvillage.com/aaj/032001.htm "Palladium: Prices" United Nations Conference on Trade and Development (UNCTAD): Info Comm http://www.unctad.org/infocomm/anglais/palladium/prices.htm "Gold Depository: Precious Metals" WHYYTV12: Secrets Beneath the Streets http://www.whyy.org/tv12/secrets/gold.html None of these precious metals web sites actually explains why a decimal like .9995 is the same as a percentage like 99.95%. So I searched for a good web site on mathematics. A helpful web page from a Syracuse University web site explains that "percent" means "per one hundred". Thus, for example, 63% is the same as the fraction 63/100, or in other words 0.63 (or just .63). So, to convert a percentage to a decimal, divide the percentage by 100. This is the same as moving the decimal point two places to the left. To convert the decimal back to a percent, you can multiply the decimal by hundred, or move the decimal point two places to the right. These rules work just as well for percentages or decimals with more than two digits. The web page has the example of the percentage 117% and the decimal 1.17  to go from the percentage to the decimal, divide by 100 or move the decimal point two places to the left, and to go from the decimal to the percentage, multiply by 100 or move the decimal point two places to the right. "Review of Percents" Center for Support of Teaching and Learning at Syracuse University: SelfInstructional Mathematics Tutorials http://cstl.syr.edu/fipse/Decunit/percent/percent.htm These rules also solve the question you have asked. If you divide 99.95 by 100 ("per cent") or move its decimal point two places to the left, you get .9995. And if you multiply .9995 by 100 or move its decimal point two places to the right, you get 99.95%. Or you can think of it this way. If you have 99.95% of a dollar, that would be 99.95 cents (hundredths of a dollar), which you could express as the decimal $0.9995. So likewise, if a coin contains 99.95% platinum, its platinum content can be expressed as .9995. I hope this answers your question to your satisfaction. If not, I will gladly provide a clarification.  justaskscottga Search terms used: ".9995" "99.95%" ".9999" "99.99%" converting decimal percent  
 

stockzguyga
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Subject:
Re: Is .9995 the SAME as 99.95%
From: cheesega on 22 Jun 2002 15:53 PDT 
This is not a complicated math calculation. justaskscottga explained it well, but I'll do so anyway. one whole is 100% 1 = 100% one half is 50% 0.5 = 50% to convert decimal to percent, just multiply by 100, which is the same thing as moving the decimal right two places. 0.75 = 75/100 = 75% percentage, as stated, is just short for for "per one hundred." 
Subject:
Re: Is .9995 the SAME as 99.95%
From: stockzguyga on 22 Jun 2002 16:09 PDT 
Guys/gals I am emailing the question to my great friend and mathmatician, Lenny. He may have a reason why they represent it as .9995. Maybe the coin dealers think this is a "purer" metal representation than 99.95%. As for me, I am staying with the US Mint' 99.95% figure, as that is a much easier symbol to convert than either .9995 or .9999 contents. If any coin dealers or jewelry persons read this, please add comments. 
Subject:
Re: Is .9995 the SAME as 99.95%
From: xyga on 22 Jun 2002 16:44 PDT 
99.95% = 99.95 / 100 = 999.5 / 1000 = 9995 / 10000 = 0.9995 
Subject:
Re: Is .9995 the SAME as 99.95%
From: xyga on 22 Jun 2002 16:50 PDT 
...whether you use 0.9995 or 99.95% is purely a matter of personal preference. The average person on the street is going to be more familiar with percentages. Metallurgists (and scientists and engineers in general) probably find factors more convenient to use. If you know a coin is 0.9995 pure platinum, you can multiply its weight directly by 0.9995 to get the amount of platinum in it. But if you use percentages, then you must divide by 100 and later multiply by 100 to get the same figure. 
Subject:
Re: Is .9995 the SAME as 99.95%
From: taratr98ga on 22 Jun 2002 17:51 PDT 
Really  the point is moot. Mathematically, 99.95% is EXACTLY EQUAL to .9995. The % percent sign (literally, percent  CENT is latin for 100) means perone hundred. That is to say, out of 100 elements, 99.95 will satisfy the prerequisite. 100 * 99.95% = 99.95. If we think of 99.95% as 99.95 elements PER 100: 100 * 99.95/100 = 99.95. (Duh.) Thereby, if we use X to represent 99.95% as the variable X: 100 * X = 99.95. X = 99.95/100 X = .9995 The difference between 99.95% and .9995 is MERELY SEMANTIC. Nothing more. Ask any mathematician  when it boils down to numbers, they are exactly the same. Bar none. Hope this clears up the issue. 
Subject:
Re: Is .9995 the SAME as 99.95%
From: stockzguyga on 22 Jun 2002 19:17 PDT 
OK everyone thankz for all the input/comments, I'll be over in the corner banging my head against the monitor for a while :). No really, we could go on for a long time over this, I get the point and I'd like to give kudos to everyone who helped on this. I realize that decimals absolutely need to be used in many cases, such as when using a gallon of water' weight. And, of course, for tolerances, machining etc. 
Subject:
Re: Is .9995 the SAME as 99.95%
From: astra4ga on 23 Jun 2002 02:05 PDT 
Gee, StockzGuy, you really appear to be mixing up something here, but I have the impression the basic problem is you don't see the difference between absolute and relative measures. Relative measures are indicated by a factor (e.g. one hundredth of something, aka 1/100, 0.01 or 1%, that's just different notations). A factor doesn't have any unit. Absolute measures on the other hand, do have a unit (meter, gallon, dollar, etc.) Tolerances, for example, are usually indicated in absolute values, the length of a mechanical part for example, could be 10 mm, +/ 0.1 mm. The same tolerance, indicated as a factor, would be 0.01 (or 1%) because 10 mm x 0.01 = 0.1 mm. But if the part is, say, 20 mm, the same tolerance (+/ 0.1 mm) turns out to be 0.02 (or 2%),... 
Subject:
Re: Is .9995 the SAME as 99.95%
From: prozga on 31 Dec 2003 23:31 PST 
.9995 * 100% = 99.95% just consider the % sign as a coefficient 
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