Can I just say I hate, hate, hate TI calculators?

I dislike calculators in general because the students don’t know how to interpret the results it gives.

Ex: Student – “Mr. Bennage, can you help me? I’ve done this problem 5 times and my calculator gave me 5 different answers.”

Me – “Well, show me what you are trying to do.”

Student shows me a formula with numbers plugged in.

Me – “Okay. Now show me how you did that on your calculator.”

Student punches in some numbers and operators with lots of parentheses – gets a 6th answer.

Student – “I’m not sure what I did. Can you just tell me what I need to push?”

Even better example that I dislike:

Student needs to add simple fractions. Uses calculator. Why?

But, why I hate the TI calculators:

4 BIG reasons.

1) Orders of operation. Yes, they should need to know and be able to apply them to do calculations. But, I’ll admit myself that I overuse parentheses on a TI to make sure I enter it correctly. I (rightly so) get the correct answer when I do it. Students invariably get 6 answers like in my first example.

2) Negative signs. Goes along with number 1, but students don’t connect them. Student needs to do -3^^{2} They usually give the answer as -9. “I punched it in like it is written.” Ugh!

3 and 4 go hand-in-hand also

3) Reciprocals. The TI uses x–^{1} notation. Students have no idea what it means or how to use it. Despite the fact that I went over it 20 times.

4) Inverse trig functions. Again, the TI uses sin–^{1} notation. Looks the same. “Don’t I just use it when I want to flip it upside down?” (cosecant -after they finally know what reciprocal does).

Obviously there is some teaching I’ve missed messed up. But, why can’t TI get it right like an HP?

I love my HP 48G. RPN is the only way to go as far as I’m concerned. And, for science class, I can use the stack to keep numbers from previous calculations without copying them down or putting them in memory for accuracy’s sake.

HP’s inverse/reciprocal notation, RPN, and text book orders of operation process make the 4 reasons go away. I don’t have any of those issues using an HP.

1/x makes more sense. asin can mean anti-sin (reverse the function). I can enter -3^^{2} and get 9. I never (almost) use parentheses and my calculation is correct.

Here are the screen shots of the 2 calculators:

Did I mention I hate TI calculators? Too bad every textbook publisher uses them with keystroke guides these days.

Just my soap box for the day. Anyone have advice?

No advice, but I’ll add one more rant:

Students entering numbers in scientific notion as

6.02*10^23

instead of

6.02E23

which another place for error.

Why does the EE key have to be a 2ND function? It deserves its own button.

Oh yes. Forgot that one.

Another reason I like my HP – it does have its own button.