kitchen table math, the sequel: the one hundred dollar calculator

Wednesday, September 5, 2007

the one hundred dollar calculator

C., age 13, 8th grade, was required to purchase a 100-dollar calculator for school this year.

Today was the first day of school. It is now 5:05 pm.

"Do you know where my calculator is?"

No. I do not.

Nor does his father.

"It's probably in my locker."


TI 84 page on ebay
"instructional time issues"
hundred dollar calculator
178 days left 'til summer
email to the principal re: hundred dollar calculators
other people's money
what is the opposite of a silver lining?

8 comments:

Tex said...

And, hopefully, his locker is actually locked.

Boys will be boys.

SteveH said...

What's the deal with graphing calculators? My son will need one sometime this year. I haven't studied them yet. What's their purpose? To avoid the need to know how to look at an equation and see its shape? To avoid understanding?

Have they decided that there is no need to be able to look at an equation like this:

y = 3(x-1)^2 + 2

and be able to immediately sketch the shape?

How about:

(x-2)^2 - (y+3)^2 = 4


Can graphing calculators plot this implicit equation? Or, are they limited to explicit functions only?

le radical galoisien said...

To calculate ugly integrals on the AP Calc exam without having to do them by hand (so you can be rewarded for remembering how to apply the Fundamental Theorem rather than being able to calculate the integral of the arcsecant in your head).

Otherwise, I think graphing calculators are just fancy attempts to look like you're fashioning a fancy progressive syllabus and introducing advanced material at lower grades when you are actually regressing.

What Singapore secondary school math did was require us to draw extremely precise graphs by hand and do it with a bendy-ruler. For a while in sec 2 I was befuddled about quadratics and the enigmatic nature of trying to fit in values that somehow magically resulted in such a beautiful arrangement but for reasons I didn't really understand.

Then after drawing the 20th graph or so, something clicked. (Drawing, not sketching!)

I remember for a good part of the unit we simply graphed quadratic functions without being told the properties of transformations of whether the graph curves up or down and so forth. I think this gives you an intuitive sense of what the graph will look like, before you learn anything else.


For example, we were only told later that having a positive a-value leads to the graph curving up. But usually because the graphing was so exact and the t-tabling so tedious, usually we began to notice patterns and we took shortcuts. Like, "gee, this last addition value only moves the thing up and down", or "increasing the b value will probably make the vertex appear sooner".

THEN the teacher informed us of the properties of quadratic graphs to ease our pain and suffering. Because of all the toil we put into it, we usually remembered those rules well, because we picked a lot of them intuitively by graphing with precision again and again and again.

"Can graphing calculators plot this implicit equation? Or, are they limited to explicit functions only?"

You can graph it piecewise.

I remember being peeved in the AP exam when I had to graph an indefinite piecewise integral in order to get a picture of the various intervals of quantity function (as opposed to rate), and then getting syntax errors because I forgot how to graph piecewise. I didn't know that would be featured on the exam as a calculator feature! Trying to visualise the antiderivatives separately then putting them together was a nightmare. (It was the 2007 free response, qn. 2)

Also, if you need a graphing calculator to do your homework but have lost it, there are always online graphing calculators. And Mathematica. Or Excel.

SteveH said...

"I remember being peeved in the AP exam when I had to graph an indefinite piecewise integral in order to get a picture of the various intervals of quantity function (as opposed to rate), and then getting syntax errors because I forgot how to graph piecewise."

There are AP questions that depend on one's ability to use a calculator??? Can you bring in a laptop with Mathematica on it? Why not? It's the same idea.

I was in college when calculators first came out. All tests changed (for the better) by focusing on manipulation of equations, rather tnan calculating numbers by hand. You could have a calculator in the exam, but it wouldn't help.


"Otherwise, I think graphing calculators are just fancy attempts to look like you're fashioning a fancy progressive syllabus and introducing advanced material at lower grades when you are actually regressing."


"Brown University President Ruth Simmons has made a $25,000 personal donation to help purchase graphing calculators for the entire ninth-grade class at Hope High School." ... May 9, 2007, The Providence Journal

"When Texas Instruments approached her about its Algebra in Motion project, Simmons thought, 'Why not do this in Providence?'"


Algebra in Motion equals Money in Their Pockets.

Rather than solve real problems in the early grades, they throw a technological, feel-good, quick-fix at the problem. It won't change a thing.


"'Some people think this is controversial,' said Sean Geoghegan, a math teacher at Hope. 'But the world is changing. All of our Brown students know how to use this technology and today’s high school students will be asked to do the same.'"

"the world is changing"

Calculators didn't get kids into Brown.


"Yesterday, Providence Mayor David N. Cicilline, who joked that he is 'math phobic,' said that this is the beginning of a strong partnership between 'a great university, a great high school and a great company.' And Arthur Petrosinelli, one of three principals at Hope High School, praised Simmons and Texas Instruments for helping Hope on its road to academic recovery."


We can analyze things all day long, but if this is the attitude and understanding of our school and civic leaders, then all is lost.


"Last year, Brown University began to outline specific areas in which the university could make a difference in the public schools, specifically in math and science instruction. The discussion is part of a larger commitment by Brown to improve public education in Rhode Island, specifically in Providence. Last fall, the 17-member Steering Committee on Slavery and Justice wrote that one of the most meaningful ways for Brown to take responsibility for its past is to improve the quality of education, especially in the urban districts."


Committee on Slavery and Justice.

Who needs enemies when you have friends like this?

Improved quality = More calculators


"Brown has since promised to devote millions of dollars to improving public education in the Providence area, including a $10-million endowment to create an education fund for the city’s children."

Let's see how many of these kids get accepted to Brown.

SteveH said...

"When Texas Instruments approached her about its Algebra in Motion project, Simmons thought, 'Why not do this in Providence?'"

I went to the TI web site and Googled "Algebra in Motion project", I came up with nothing. All they had was something about "Math and Science in Motion" for middle-schoolers, not ninth-graders.

The president of Brown University bought into this for $25,000 of her own money.

Catherine Johnson said...

What Singapore secondary school math did was require us to draw extremely precise graphs by hand and do it with a bendy-ruler.

shoot me

Catherine Johnson said...

If this calculator is lost, I'm not buying another one.

Catherine Johnson said...

famous last words