Using Hyphens to Indicate Place ValueDate: 08/30/2004 at 20:23:41 From: Joe Subject: place value What is the difference between the following two numbers: five hundred thousandths five hundred-thousandths They seem the same to me, but my teacher says that they are different. The 1st one is written as 0.500, but I do not know how to write the 2nd one. Date: 09/01/2004 at 09:59:50 From: Doctor Wilko Subject: Re: place value Hi Joe, Thanks for writing to Dr. Math! This is a great question and shows why we should hyphenate the place value of decimal fractions. You might want to start by reviewing this from our archives: Writing Numbers with Hyphens http://mathforum.org/library/drmath/view/63129.html If I ORALLY told you and a friend to write the number, "five hundred thousandths" you might write 0.500 and your friend might write 0.00005. Who would be correct? Well, both of you could be--it's not clear which way I meant since they both SOUND the same. If I say (in writing) to write five hundred "thousandths", the place value that I'm stressing is thousandths. So, write the number 500 so it ends in the thousandths place: 0.500 On the other hand, if I say to write five "hundred-thousandths", the place value that I'm stressing here is the hundred-thousandths place. So, write the number 5 so it is in the hundred-thousandths place: 0.00005 Do you see the difference now? The hyphen helps us decide if the hundred is part of the thousandths, making it hundred-thousandths, or part of the five, making it five hundred. Since we don't speak the hyphen, we often try to communicate it by using a slight pause as we speak. We might say: five....hundred-thousandths to mean 0.00005 five hundred....thousandths to mean 0.500 Just to drive the point a little further, write these out as fractions and convert them to decimals. five hundred "thousandths" = 500/1000 = 0.500 five "hundred-thousandths" = 5/100,000 = 0.00005 Does this help? Please write back if you have further questions. - Doctor Wilko, The Math Forum http://mathforum.org/dr.math/ |
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