[Numeracy 156] Re: The double negative language-math link
Archived Content Disclaimer
Please note: This page contains archived content from the lincs.ed.gov e-mail discussion list system, which was disabled in 2012. The content on this page is available for archival purposes only. Hyperlinks on this page may be broken or may no longer link to the content specified from within the archive posting. In addition, information displayed on this page may no longer be relevant.
Fri Feb 12 13:07:51 EST 2010
- Previous message: [Numeracy 155] Re: The double negative language-math link
- Next message: [Numeracy 164] Re: Integers and language
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Actually, you can subtract with money. Think in terms of a credit card. Say
they have charged you a $29 late fee (or is it more now), and you challenge
the fee for a legitimate reason, so they have to remove (subtract) the late
fee. That actually means *adding* the $29.
On Fri, Feb 12, 2010 at 9:18 AM, Leslie Hunten <lhunten at gmail.com> wrote:
> I like the sea level analogy. If I hike down into Death Valley, I'm going
> down below zero in elevation, because sea level is the arbitrary zero and DV
> is deeper. However I'm not hiking backwards, nor using an anti-gravity
> chair, I'm definitely taking steps and I can count them as an absolute
> number in a negative direction. So I might walk a few miles, which are very
> real to my feet, but now I'm at a negative number on an elevation map. When
> I hike back out, and perhaps even climb to the peak of a mountain, I'm
> walking in the positive direction. But it feels the same to my feet - I'm
> still walking forward. My total distance could be called the absolute
> number of miles I walked, and my elevation change has to be in negative and
> positive numbers. I could walk 10 miles and have an average elevation of
> But frankly, I think the most realistic analogy in integers for students is
> with "having and owing money". That's a scenario they're all familiar
> with. Unfortunately, this only works with adding, not subtracting. But if
> you spend quite a while exploring neg & pos with money situations, they
> should get a good grasp of the concepts. After that, I tell them, "Sorry,
> now you just have to memorize a few rules, because they don't really make
> logical sense. Just do it."
> By the way, I just joined this list, and I love it already!
> On Thu, Feb 11, 2010 at 10:57 PM, Claire Ludovico and/or TJ DeLuca <
> tjdclaire at cox.net> wrote:
>> There is always above and below sea level...
>> I use bank accounts as the most likely exposure of my students to negative
>> numbers...and the minus a negative example is when one finds a charge (funds
>> subtracted) that has been (incorrectly) imposed by the bank that is then
>> removed (taken away) from your balance...or in other words, they returned
>> your money to you.
>> I once had to introduce integers to a group in a very limited amount of
>> time. I made up a story about the positive tribe and the negative
>> tribe...both very warlike but only with the other tribe, never with each
>> other. Positives, of course, carry two spears, negatives only one. They
>> have very strict rules of warfare: only one positive may fight a negative
>> ...no ganging up...and when they fight (so sad) both die. They can hang out
>> with their own kind, of course, no problem. (Addition)
>> Subtraction: They are also both very greedy...so in their wanderings in
>> the woods, if they should spy a new spear laying on the ground (the minus
>> sign) the positives, who have a spear in each hand, must throw away their
>> two spears in order to pick up the new spear (and thus become negative) and
>> the negatives, who carry only the one spear, can reach down and pick up the
>> new spear...and become positive. Then those former negatives can hang out
>> with positives (and vice versa) but can no longer face their former kind
>> without "war" breaking out.
>> Miraculously, the two tribes can marry (multiply) and the *product* of
>> their union depends on their signs (multiple marriages allowed (perhaps each
>> parent "gifts" the same number of spears as he/she carries)...count the
>> negative signs: odd number, the "children" are negative, even number (two
>> spears again) the "children" are positive.) Divorce (division) is quite
>> possible and the rules are the same as for multiplication.
>> I don't know if my students always get why I tell the story (but then they
>> don't always get the rational explanation.) As I said, I usually back up
>> the problems with bank account analogies. But the spear story helps
>> sometimes if you have a negative (or minus sign) outside parentheses and you
>> can talk about shooting the spear through the parentheses and changing the
>> sign of everything inside.
>> Also, my students were looking at the problem yesterday: (-6) - (-1) = ?
>> I was able to say," If you have six negative guys and you take away one of
>> them, how many are left?" They got it.
>> On 2/11/2010 8:17 PM, Denney, Brooke wrote:
>> I disagree with your statement that, “negatives carry meaning in
>> mathematical, but not physical (reality) terms”; after all, it is winter in
>> the Midwest and negative values mean something in my reality when we are
>> talking about wind chill factors and really cold temperatures (perhaps
>> living in a really warm climate you may have forgotten). Also, negative
>> numbers are used when discussing the grade of the road (i.e., positive or
>> negative grade). Does anyone else have examples of negative numbers used in
>> National Institute for Literacy
>> Math & Numeracy discussion listNumeracy at nifl.gov
>> To unsubscribe or change your subscription settings, please go to http://www.nifl.gov/mailman/listinfo/numeracy
>> Email delivered to tjdclaire at cox.net
>> National Institute for Literacy
>> Math & Numeracy discussion list
>> Numeracy at nifl.gov
>> To unsubscribe or change your subscription settings, please go to
>> Email delivered to lhunten at gmail.com
> National Institute for Literacy
> Math & Numeracy discussion list
> Numeracy at nifl.gov
> To unsubscribe or change your subscription settings, please go to
> Email delivered to dickins2 at wncc.edu
-------------- next part --------------
An HTML attachment was scrubbed...