CASIO fx-991CW Classwiz - Beware of its flawed Scientific Notation implementation

[@cret859]

Thank you Scott for this very clear explanation. Since this [x10^] key is placed under the numeric keypad, it is easy to believe that it is an EE, EEX or Exp key. But no! A third solution is to change the order of the opérations you enter; at first you type your computation with only the mantissa and then terminate with the teen-exponent section at the very end. A bit like we made in the far past with slide -rules. For your exemple : 1÷1 [×10^] ⁶ˉ³ [EXE]. Having only one occurrence of this [x10^] key entry in the expression may avoid any ambiguity.

[@scottcollins7513]

Thank you for the kind words and for taking the time to leave a comment. It is a shame that it requires any sort of special handling when it is something done well by calculators for the past 40 years or more. But, thanks for pointing out another approach that might be taken. My biggest concern is for the many high school and college students for whom math is already challenging enough, having to use a work-around for something so routine.

[@theedspage]

I have not noticed this before, and I agree this is a flaw in the design of the fx-991CW. If I store 1 * 10^6 and 1 *10^3 in variables, say A and B respectively, and then divide A ÷ B, I get the proper answer of 1000. Thank you for the shout out, Scott. - Edward Shore

[@scottcollins7513]

Good idea to check how it performs when storing the numbers in variables. I would not have thought to try that. Glad to know it behaves properly. Take care, Edward -- always good to hear from you!

[@alexandredeoliveirapenna198]

Thanks scott! Its a shame the old one isn't available anymore... i got one used in pristine state last year to use on master degree due to the prohibition of programmable calculators on my course, and have no regrets. But I still prefer my hp32s in my daily use

[@scottcollins7513]

The new one is still good, but I do prefer the 991EX. I've never used an hp 32s, but I'm sure that is a nice device. You have 2 winners!

[@MrMarcec85]

I am glad I have bought the ex when I could, because the cw looks a like product rushed to market without proper engineering (not only for this flaw). Thanks because I would have never understood that.

[@scottcollins7513]

Glad you found the video informative. I'm still surprised they made this "error" w/ such a key product. CW is still respectable, but EX is better. Thanks for leaving a comment.

[@REDIDSoft]

Excelent vídeo, I almost pick this Casio, but intead got the Hp prime

[@scottcollins7513]

The 991CW is still a good calculator, but the Prime is in a completely different league -- in fact, it is too complicated for me, though it is an impressive device. Have fun w/ it!

[@TheSuperUser]

Nice demo. This is obviously a design flaw by Casio. I think to be 100% sure one should always use parenthesis to avoid confusing the calculator and double check you work. I think 991ex is still the king of the Casio lineup.

[@scottcollins7513]

Thank you for leaving the kind words. Yes, using parentheses for everything is the safest route, but what a headache. 991EX is the best in this price range in terms of performance and quality. Like I said in the other comment, I actually like the 115ES Plus 2nd Ed more, but that is b/c I think it is a bit more straight-forward, has a bigger font, and offers a few more features.

[@ys-fz9mt]

​@scottcollins7513 hi so do u think the 115ES Plus 2nd Ed is better than the CW?

[@ys-fz9mt]

​@scottcollins7513 my first choice was the 991ex however I can't buy it anywhere. These are the available ones 991cw 115es plus 2nd Ed Ti 36x Ti 30x pro mp The ti 30x pro mp is 70 while the rest are only 30 is it worth it to pay more for the ti 30x pro mp?

[@scottcollins7513]

@@ys-fz9mt Depends what you prioritize. Personally, I prefer the 115ES over the 991CW bc I can get to what I need more quickly and the way it works is fully thought through (ex: scientific notation). I'm willing to give up some speed and display quality.

[@scottcollins7513]

Just realized you had more in your list. If you take good care of your things, can afford the additional $40 w/out too much pain, and if it is something you will still be using 5 years from now, I think the TI-30X Pro MultiPrint would be the best. If value is highest priority, I would choose either the 115ES Plus 2nd Ed or the TI-36X Pro. 991 CW would be my last choice, but it is still respectable.

[@DheerajGujrathi2005]

Maybe because they use Pamdas rule, I thought this because they said they are using notebook notation, hence, we are expected to write Equation in the way we would Interpret it if no brackets were given

[@scottcollins7513]

I think the big problem is that they have turned scientific notation into multiplication which is not the same. Whether I say 1,000,000 or 1E6, I am representing a single number and not a product. I am not going to let them off the hook on this one. Regardless, I do appreciate you leaving your thoughts. Always good to hear what others are thinking.

[@Silizium_]

can you show how the matrices function work?

[@scottcollins7513]

Sure. It may be a few weeks before I get to it, but I will make a point to cover Matrices and Vectors. Thanks for the suggestion.

[@Silizium_]

@@scottcollins7513 thanks that will help me a lot!

[@abather11]

Can do a video on casio fx 5800p plz

[@scottcollins7513]

@@abather11 I do not own that calculator. I will do some research on it. Regardless, thanks for the suggestion!

[@JohnnieMartynov]

Ehh, really not expected!

[@dgm2006]

This is serious. I think they changed this because it makes the numbers look prettier. Another really bad decision by Casio.

[@scottcollins7513]

I am really surprised it got through all the testing. I think there are going to be a good number of students who get confused by it.

[@jenselstner5527]

Maybe there is an option to switch. Else is very bad behaviour.

[@scottcollins7513]

Based on your comment, I just now checked to see what would happen if I set the calculator in Scientific Notation mode, but it still behaves badly -- it just says 1x10^9 instead of showing 1,000,000,000. Not good.

[@jenselstner5527]

@@scottcollins7513 It's just another reason to use RPN calculators. 😉

[@scottcollins7513]

@@jenselstner5527 Ha! Nice. RPN will always be first in my heart.

[@sarimsalman2698]

​​​​@@scottcollins7513I'm a young student (16 y/o) and I've recently fell in love with RPN. I heard people saying that it is only used for nostalgia but after actually trying it, I realise those people are wrong. HP 48 is amazing

[@maxrkmrose]

What a piece of poor programming.

[@scottcollins7513]

Yes. It is rather amazing that it was released this way.