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Saturday, December 21, 2013

Math topics that need to be put out of their misery. Part 2: Absolute value | Gary Rubinstein's Blog

Math topics that need to be put out of their misery. Part 2: Absolute value | Gary Rubinstein's Blog:

Math topics that need to be put out of their misery. Part 2: Absolute value

The old math standards, say common core defenders, were “a mile wide and an inch deep.”  I’m inclined to agree with this.  Too many topics and too little time led to teachers having no choice but to teach many topics at a superficial level.  As time in a math class is a somewhat fixed quantity (unless you want to do ‘double blocks’ in math which, of course, is taking away from something else which is equally, if not more, valuable), the only feasible solution is to cut out some, if not many, topics.
The common core writers missed a good opportunity to do this, however.  The standards do specifically describe certain ‘topics’ that are required, but not all topics are explicitly described.  This leaves the teacher, school, or district, in a strange predicament:  If they skip a ‘topic’ which was not specifically described in the standards and then that topic appears on the nationally ‘aligned’ common core tests, that teacher, school, or district may find themselves punished for not being ‘accountable’ enough.
One such topic which is ambiguously hinted at in the standards is part of this second part of my (probably ten part) series about math topics that somehow were put into the curriculum years ago and continue despite the fact that they serve no purpose whatsoever.  That topic, which plagues kids starting in about 6th grade, is ‘absolute value.’
For those of you who have forgotten (or maybe have just repressed memories of it) the official definition of ‘absolute value’ is “the distance a number is from zero on the number line.”  So the number five has, we say, an absolute value of five since five is five away from zero.  But five is not the only number that has an absolute value of five.  Negative five also has an absolute value of five since negative five is also five away from zero (on the other side of zero) on the number