Writing Decimals from Words
Date: 10/05/98 at 01:19:21 From: Lisa Subject: Writing decimals Can you help me with my assignment? Here's a sample question: Write the decimal for five hundred seventeen thousandths. Please help, Lisa
Date: 10/05/98 at 16:53:10 From: Doctor Rob Subject: Re: Writing decimals Lisa, The first thing to do is to figure out where the fraction bar should go. The numerator will be a simple number, and the denominator will be a number with -ths on the end (like "three tenths": the numerator is "three" and the denominator is 10 because of "tenths"). Since these are specified to be decimals in the statement of the problem, the denominator will be a power of 10: tenths, hundredths, thousandths, ten thousandths, hundred thousandths, millionths, and so on. Figure out starting from the back where that part starts. Put the fraction bar just before that, and drop the "-ths" off the end. Then write the number before the fraction bar as the numerator, and the number after the fraction bar as the denominator. In your example: "five hundred seventeen thousandths" since "seventeen thousandths" is not a power of 10, it cannot be the denominator, so the fraction bar must go between these words. Then you have: "five hundred seventeen / thousand" or: 517/1000 Now divide the denominator into the numerator by moving the decimal points of each to the left the same number of places as the number of zeroes in the denominator (in this case, three places left): .517/1.000 = .517 and that is your answer. WARNING: Sometimes there are two answers, and you can't tell which is correct. As an example, "One hundred ten thousandths" could mean 110/1000 = .110, or 100/10000 = .0100 (think about it). When the words are spoken, a slight hesitation indicates the position of the fraction bar, removing the ambiguity. The first would be pronounced as if it were written, "One hundred ten, thousandths," and the second as if it were written, "One hundred, ten thousandths." Of course the comma is never written, just understood. Good luck! - Doctor Rob, The Math Forum http://mathforum.org/dr.math/
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