Placement of Commas in Writing NumbersDate: 10/22/2003 at 10:20:19 From: Beth Mearkle Subject: Place Value Why is the ones period named for the ones place value and why is the thousands period named for the thousands place? Why is there not a hundreds period? Date: 10/22/2003 at 12:26:46 From: Doctor Peterson Subject: Re: Place Value Hi, Beth. We do, of course, have a PLACE for hundreds; but PERIODS are divided by thousands, to match the way we say numbers aloud: 123,456,789 = 123 million, 456 thousand, 789 [units] So each period is named for the value of its least significant digit, and each period contains three digits. There is no real mathematical reason for doing this, apart from the value of consistency; it is just a good match with English (and most other languages). You may be interested in the fact that in India, commas are put in irregularly, to match an irregular set of number names: Numbers in Hindi and Urdu http://mathforum.org/library/drmath/view/57179.html In their language, a lakh is what we call one hundred thousand (100,000), and a crore is our ten million (10,000,000). In order to match how they say numbers, they write a lakh as 1,00,000, and a crore as 1,00,00,000. So, since we read numbers as "XXX thousand, Y hundred, ZZ", we could very well have chosen to write numbers as XXX,Y,ZZ. But I think it's good that we don't, because it would be confusing, and would not help much if any. Perhaps we were saved from that by the fact that we don't normally put a comma after "hundred" when we write out numbers (or a pause when we read them), so the comma did not seem necessary. Also, the fact that we say "hundred" within the other periods would force us to write X,XX,Y,ZZ, and we just don't need that many commas. If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/dr.math/