kitchen table math, the sequel: Graphing Calculators

Friday, August 20, 2010

Graphing Calculators

My son is required to buy a $100 TI-84+ graphing calculator for his Algebra II class this fall. I'm not thrilled about this; the cost or its use. Does anyone have any comments about these calculators or their use in high school math?
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31 comments:

Anonymous said...

My son had to use a graphing calculator in his Honors Algebra 2 class, and they are expected for the AP Calculus exams. Luckily he already had 3, won as middle-school math prizes, so even after one was stolen mid-year he could continue without difficulty.

Although calculator use is not essential to algebra, the teacher made good use of the in class and in homework, without turning them into a crutch. More importantly for my son, programming the graphics calculator provided entertainment in class when the class went far too slowly.

August 20, 2010 at 11:05 AM
Anonymous said...

Put his name inside the battery lid, so that if it gets taken you have a hidden name on it and can prove it is his.

Carving his name in the name area on the back also stops thieves from lifting it.

August 20, 2010 at 11:06 AM
Catherine Johnson said...

I'm getting one soon myself. One of my SAT math prep books advises using it on the test.

I want to learn how to use it in any event.

Which reminds me.

I have a problem I'm hoping some of you will help me out with.

August 20, 2010 at 12:01 PM
Anonymous said...

Graphing calculators have been expected at the pre-calc level since 1990, at least. Unless the new ones are solar or rechargeable, batteries are important; they used to be in short supply just before important tests.

August 20, 2010 at 12:08 PM
Anonymous said...

Math kid says he uses his daily and on most tests.

We were cleaning out his closet the other day and I came upon a ton of graphing paper. He said he didn't need it because he has the graphing calculator. Then he did the eye roll thing meaning, "God, you're old."

In our school, the calculators are stolen quite often and then sometimes sold right on school property. Definitely have his name on it where it can't be taken off.

That's a good idea about the inside of the battery lid.

SusanS

August 20, 2010 at 12:26 PM
SteveH said...

Thanks for the feedback.


"One of my SAT math prep books advises using it on the test."

Is there a limit to the calculator or the programmability?


On my son's Geometry final last year, I told him that he should use his own calculator. He didn't think it was necessary, but then proceeded to waste time before he figured out that the calculator he was using was set to radians.

August 20, 2010 at 12:30 PM
Catherine Johnson said...

I don't think there's a limit to programmability for SAT.

GMAT doesn't allow any kind of calculator at all, not even a cell phone.

August 20, 2010 at 12:37 PM
Independent George said...

You know what I want to know? Why does my cell phone have 1000x the computing power of my old Apple IIC, at 1/3 the nominal price - while the TI-84 costs even more than my old TI-82 after the same time lapse?

August 20, 2010 at 12:41 PM
Mark said...

I graduated from high school in 1991, and have never owned a graphing calculator (minored in Physics at UC Berkeley, majored in Computer Science). The calculator isn't important IMO and in fact can be a distraction because you spend more time figuring out the device than learning the math.

That being said, you may want to ask why it's required. There are free programs for computers that can do all that the graphing calculator can do and more, and if it's not used in class it shouldn't be required.

August 20, 2010 at 1:03 PM
Daniel Ethier said...

In reply to Independent George, xkcd has the following:

http://xkcd.com/768/

August 20, 2010 at 1:50 PM
Rachel said...

TI-84+ calculators are terrible. Even Casio does a better job. I got through Algebras I and II, Geometry, and Calculus with Topics in Multivariable without a graphing calculator. Pick up a $15 scientific calculator and teach him to graph things on paper instead of relying on a machine.

August 20, 2010 at 2:31 PM
Catherine Johnson said...

hmmm....

maybe I'll forget the graphing calculator...

August 20, 2010 at 2:37 PM
Catherine Johnson said...

Are there graphing calculator web sites you all like?

August 20, 2010 at 2:38 PM
Unknown said...

I got a free Casio fx-9860GII graphing calculator. It's WYSIWYG program is really nice. My son's teacher said that part of his Alg 2 course is teaching how to use a TI-85. I let him check this Casio out, but he felt the calculator provides *too* much help.

They provide a TI-85 to students that don't purchase their own, for now. As the school grows, they are hoping to get a donation or grant for more.

Many colleges rent them by the semester for $20. That's what I did.

I believe that by law, schools can not *require* students to purchase any type of school supplies. That said, who wants their kid to get the junk provided by the school, when about $20 gets them their own supplies?

I have never purchased a container of Purell or hand sanitizer that always shows up on those lists for any school we've attended and no one complains. In fact, I wait until January or so and just provide restocking of tissues or dry erase markers when I find a good deal. Never had a teacher complain yet.

August 20, 2010 at 3:32 PM
Unknown said...

Ahh, someone at wikihow said it better than I did:

"Consider not buying anything. In the USA, all state constitutions require that children in the state have access to a "free public education." Requiring payment of fees or purchasing of supplies in order to attend public school may be very common, but it is not lawful. Remember, however, that teachers often have to supply items out of their own pockets for students who don't bring supplies. Making a stand when you really could afford basic school supplies can pass this burden on unfairly."

August 20, 2010 at 3:42 PM
Catherine Johnson said...

Cassy- thank you!

You all just saved me from buying a ludicrously expensive graphing calculator ---

August 20, 2010 at 5:59 PM
SteveH said...

"while the TI-84 costs even more than my old TI-82 after the same time lapse?"

Hey! I thought the same thing when I saw the price. I can get a full-function scientific calculator for less than $20.

That specific calculator is featured and demonstrated in the textbook. (Gotcha!) His textbook cost me $100, by the way, and weighs a ton. I'm buying his own copy of all of his math textbooks so he will have well-used references in the future (and avoid lugging them back and forth to school).

I also checked his summer Algebra II packet and it said that he "might" want to buy one. It remains to be seen whether it will be a help or a hindrance in the class. I expect him to be able to figure out the shape of many equations just by examination.


However, the TI 84+ can do so much more. It's hard to believe that it's allowed on the SAT.

August 20, 2010 at 7:41 PM
John said...

I graduated high school in 1989, graduated with a college math major in 1993, graduate school math in 1995 and taught community college in 1996 & 1997. I never had to use a graphing calculator in my classes or to teach in grad school or at the community college. However, if I had stayed at comm college one more year every math class was going to use it. I don't see the need for it. You spend more time learning how to use the calculator than actually doing math. Why do kids need a fancy calculator to draw lines and parabolas? A basic scientific calculator is adequate for higher math. If you need to do anything more complicated than a line or parabola, computers can do it. In the real world of math applications or statistics, it is all on the computer. With laptops becoming so popular at the college level, these calculators are way outdated and not used in any type of math related field. I imagine there must be a deal between educational textbooks and TI to keep this product going.

August 20, 2010 at 8:03 PM
ChemProf said...

I've seen an active disadvantage to the graphing calculators, because they do so much. In particular, they allow students to just enter the whole equation at once and hit enter. They don't develop a sense of how order of operations really works (they can list them, but can't easily do a calculation in single steps). Similarly, I can't tell you how many students will type in "1.000", rather than just 1. Really learning to use a $20 scientific calculator quickly and automatically would benefit most students more than a graphing calculator.

August 20, 2010 at 9:34 PM
GoogleMaster said...

I'm a little older than the others who named years; I graduated from high school in 1982 and earned a BS in Electrical Engineering in 1986. I've never owned or used a graphing calculator. In Multivariate Calculus, we had homework where we had to DRAW BY HAND the 3D graphs of some equations and inequalities. I still shudder when I think about drawing and shading the saddle curves while lying on the grass in the sun. We also graphed things on Smith charts by hand in one or two EE classes.

August 20, 2010 at 9:48 PM
Unknown said...

I am a high schooler who is going to be a senior this year. I took the SAT this year and none of the problems technically need any use of a calculator and it really does not help that much. While the SAT II Math Level 2 is said to require graphing calculator use for 55% of the questions, in reality, it is possible to do 95% of them without any use of a calculator technically.

August 20, 2010 at 10:02 PM
SteveH said...

"While the SAT II Math Level 2 is said to require graphing calculator use for 55% of the questions, in reality, it is possible to do 95% of them without any use of a calculator technically."

I see two different issues. The first is whether the calculator is used to avoid learning certain skills in math. The second is whether the calculator is an effective tool for tests like the SAT.

I remember a question about a triangle (no angles known) where I didn't realize that it was a 3-4-5 type. It would be nice to have a calculator to quickly use a brute force method. How many SAT questions are based on "seeing" something to make the problem easier?

I love calculators (and computers), but educators seem to use them as avoidance tools. Calculators came out when I was in college, and they allowed classes to tackle more complex material.

Now that computers are so small and (relatively) inexpensive, it seems odd to be stuck with the limited capability (and user interface) of a TI calculator. They should see that their whole business may be eliminated by an app.

August 21, 2010 at 5:11 AM
LSquared32 said...

Some kids use their graphing calculators in a smart way, and it's a useful tool. Even more students use their graphing calculators to add 2+6, and it's an expensive crutch. Some teachers use the graphing calculators in a really effective way, and the calculator is a really important learning tool. Other teachers don't use the calculator that well. If you're going to buy a graphing calculator (and if your son's headed for AP Calc, it's probably a good idea--get to know your tools well, and don't leave it until the last minute), the TI-84 is one of the ones I'd recommend, though personally I'd pick up a used TI-83 on Ebay and save some money on it. If you're feeling really cheap, you can buy a used 82 and see how far it gets you (80% of the stuff an 84 does, an 82 does, and it does it in an almost identical way, using almost identical key-strokes, so switching up doesn't require much new learning). Last time I looked you could find a used TI-82 on Ebay for less than $20.

The TI-82, 83 and 84 are almost identical, with a few useful upgrades with each increase in numbers (for instance, 83's handle polar coordinates better than 82's--and of course they get more memory for programming as you go up). The 85 and 86 are similar to each other, but nothing like the 82-84 set--the 85-86 are neither newer nor more advanced than the 82-84 set so far as I can tell. The 89 is almost a computer, and does way more of the thinking than I want it to do--I don't let my calc students use 89's when taking tests (the 89 is pretty much the same as a 92, but without the keyboard--keyboards aren't allowed on AP tests--it's a test security thing, I think).

The main thing about the TI-82/83/84 series that I really like is that you can figure out 80% of how to make it do what you want it to do without ever touching the manual. You look at the keys, and you look at the menus that pop up, and everything's right there. Very short, easy learning curve. The experience I've had with 85's, 86's, 89's, and even Casio's is that you have to spend way too much time teaching students how to use the calculator/learning how to use the calculator. The classes I teach are graphing calculator optional, but I tell my students that if they are going to buy a graphing calculator it should be a TI-83 or 84 because they're user friendly (and they're more common, so if the students run into trouble, it's easier to find someone who can fix it).

August 21, 2010 at 9:43 AM
Anonymous said...

No graphing calculator allowed for the ACT. You can bring a basic one, though.

SusanS

August 21, 2010 at 11:25 AM
ChemProf said...

I got curious, so did a quick search and found that you can get Mathematica Alpha for your iphone or ipad.

http://www.wolfram.com/news/alphaapp.html

Which just cements my policy that only basic $20 scientific calculators can be used on my tests...

August 22, 2010 at 10:37 PM
Cranberry said...

The Wolfram Alpha app costs only $1.99.

August 22, 2010 at 11:07 PM
ChemProf said...

Yeah, Cranberry is right. My husband bought it and was playing with it last night, and what it can do is really scary!

August 23, 2010 at 8:27 AM
lgm said...

Here, the g.c. is a way to game the test. If the teacher runs out of time or can't get the lesson across, s/he'll resort to teaching the algorithm with the calculator. It'll also be used as a test taking strategy..faster Plus higher chance of weaker students getting problem right on the Regents exams if plugging the answers in to find the right one instead of solving the problem.


Each classroom has a class set of calculators here. Those are all that are available on exam days. Fine, except for the Regent's exam which is given en masse as each student will have to come up and get a calculator since only one is available for each 3 students.

August 23, 2010 at 10:53 AM
Anonymous said...

Is it the teacher who is trying to game the test, or the student?

Presumably, the class set of calculators is to prevent students from hacking their own calcs and storing answers and procedures they should not be?

August 23, 2010 at 7:06 PM
lgm said...

The teacher is showing how to use the calculator to check all the multiple choice answers to determine the correct one. The admin is dictating that this be done on class time, even when it means throwing out units that should have been taught (according to the Regents' objectives for the course). There is a huge incentive here to reduce the drop out rate & graduate students -- unclassified students must pass Regents Integrated Alg. I to qualify for the diploma. So there is a huge incentive to compensate for the weak course by using the calc for a few points, especially in the statistics and trig problems.

The class set is because most parents won't buy the calculator. Waaaaay too expensive, likely to be stolen, and the app for the home pc is much cheaper. Any student that wishes is allowed to use his personal TI84/Nspire on the math Regents' exams, following the protocol the Regents have established. (apologies for the unclear wording above; meant to be clearer in saying that the school will only have class sets available, not bring in extras so each student has one at his side).

August 23, 2010 at 7:32 PM
LynnG said...

My daughter's geometry class required the graphing calculator last year, so we had to buy it. The school just assumed all parents could afford to, so that was that.

For geometry, the graphing calculator was amazing, if used well by the teacher, i.e., the student must solve most equations on their own, but use the graphing calculator to pictorially show results, immediately show how any changes in the equations create a different graph, etc.

Also, teachers can take their own calculators and project their results on the board and students can see if they are getting the same results. It was useful, and now that she has a graphing calculator, we are set for the rest of the high school.

August 25, 2010 at 2:51 AM

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