Comments on: Writing out numbers with the word ‘and’ http://www.mathmojo.com/chronicles/2009/08/22/writing-out-numbers-with-and/ The Official Blog of MathMojo.com - helping public school, homeschooling, unschooling students, parents, teachers and adults learn math with easy and effective methods. Tue, 07 Feb 2012 03:05:13 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Mr D http://www.mathmojo.com/chronicles/2009/08/22/writing-out-numbers-with-and/comment-page-1/#comment-270953 Mr D Sat, 17 Sep 2011 07:45:28 +0000 http://mathmojo.com/chronicles/?p=798#comment-270953 While not wanting to engage with the emotion behind this argument (which seems pretty high, but then passion is a good thing), I thought you might like another viewpoint... As an Australian teacher with only a few years experience I have never heard anything like this convention, and while I haven't as yet checked with my colleagues, you can be sure that I will. On the surface I would have to say that using a word in frequent common usage to represent a specific mathematical concept is a very dangerous idea. Certainly this happens every day with science based terminology (ask a scientist whether a frisbee flies, glides or sails through the air and you'll see what I mean)but it still doesn't appear to be a well thought out 'rule'. In time, I believe this rule will live or die on its own merits. Did you know in Australia, to the best of my knowledge, a billion is still OFFICIALLY (mathematically) 1 000 000 000 000, (your trillion), but this has reached a state of such low usage that most people acknowledge it to be 1000 million (because they hear it said that way on the news and such, and also because it follows the pattern of renaming a number after every set of three zeros. I guess the short answer is that flexibility is required, no one is ever always right, and that discussion about maths is a great way to learn. While not wanting to engage with the emotion behind this argument (which seems pretty high, but then passion is a good thing), I thought you might like another viewpoint…
As an Australian teacher with only a few years experience I have never heard anything like this convention, and while I haven’t as yet checked with my colleagues, you can be sure that I will. On the surface I would have to say that using a word in frequent common usage to represent a specific mathematical concept is a very dangerous idea. Certainly this happens every day with science based terminology (ask a scientist whether a frisbee flies, glides or sails through the air and you’ll see what I mean)but it still doesn’t appear to be a well thought out ‘rule’.
In time, I believe this rule will live or die on its own merits. Did you know in Australia, to the best of my knowledge, a billion is still OFFICIALLY (mathematically) 1 000 000 000 000, (your trillion), but this has reached a state of such low usage that most people acknowledge it to be 1000 million (because they hear it said that way on the news and such, and also because it follows the pattern of renaming a number after every set of three zeros.
I guess the short answer is that flexibility is required, no one is ever always right, and that discussion about maths is a great way to learn.

]]> By: Just because it's taught in school doesn't make it right | The Math Mojo Chronicles http://www.mathmojo.com/chronicles/2009/08/22/writing-out-numbers-with-and/comment-page-1/#comment-161947 Just because it's taught in school doesn't make it right | The Math Mojo Chronicles Fri, 04 Sep 2009 19:21:50 +0000 http://mathmojo.com/chronicles/?p=798#comment-161947 [...] Thanks for visiting!This post was prompted by a comment made on a recent post. The post was about writing out numbers with “and.” Please read that post in order to understand this [...] [...] Thanks for visiting!This post was prompted by a comment made on a recent post. The post was about writing out numbers with “and.” Please read that post in order to understand this [...]

]]> By: J. A. Witt http://www.mathmojo.com/chronicles/2009/08/22/writing-out-numbers-with-and/comment-page-1/#comment-161911 J. A. Witt Fri, 04 Sep 2009 15:32:18 +0000 http://mathmojo.com/chronicles/?p=798#comment-161911 The use of the word "and" to indicate the decimal point is an agreed-upon "rule" in math. Math has many of these "rules," which try to clarify mathematics. This is a standard rule taught in most elementary schools. PLEASE don't confuse the students by saying they can do as they please. Then can 2 + 3 x 5 be equal to both 25 and 17? NOT. The order of operations "rule" says multiply first, so 2 + 3 x 5 = 17. <strong><em>Professor Homunculus sez:</em></strong> J.A., I'm sorry that I'm going to have to disagree vehemently with your point, and with the invalid and misleading way you go about trying to prove it. I think you are providing a perfect example of why students to not trust some of the people who teach them. It's so important to let kids know why the above argument is not only invalid, but counter-productive, that I wrote an entire post about it. Interested readers can find it <a href="http://mathmojo.com/chronicles/2009/09/04/just-because-its-taught-in-school-doesnt-make-it-right/" rel="nofollow">here</a>. The use of the word “and” to indicate the decimal point is an agreed-upon “rule” in math. Math has many of these “rules,” which try to clarify mathematics. This is a standard rule taught in most elementary schools. PLEASE don’t confuse the students by saying they can do as they please. Then can 2 + 3 x 5 be equal to both 25 and 17? NOT. The order of operations “rule” says multiply first, so 2 + 3 x 5 = 17.

Professor Homunculus sez:

J.A.,

I’m sorry that I’m going to have to disagree vehemently with your point, and with the invalid and misleading way you go about trying to prove it. I think you are providing a perfect example of why students to not trust some of the people who teach them.

It’s so important to let kids know why the above argument is not only invalid, but counter-productive, that I wrote an entire post about it. Interested readers can find it here.

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