Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Do you really need a calculator?

  1. Jan 26, 2007 #1
    How often should you use your calculator? I try to use mine as least as possible, even if it means doing trivial division or multiplication on paper or in my head. I seriously forget to use the calculator and sit there trying to figure stupid stuff out. This gets me into trouble when I make careless mistakes in my arithmetic, as opposed to the mathematics itself. I am afraid if I use my calculator, I will lose any intuitive feel for numbers, or never learn some method or concept because I didn't work it out on paper everytime.

    I only use my calculator, when I absolutely have to (sin,cos,tan and some other things). I think it's because I never used it through high school, so now I have no idea what it is even good for. I have a TI-83+, should I be using this more for Calculus?

    Is there is a proper way to use the calculator? I know these questions are silly, but again, I am self-taught so I have no outside advice to compare myself. I definitely make mistakes without one, so I am trying to figure out what the perfect balance is.
  2. jcsd
  3. Jan 26, 2007 #2
    I use my calculator for trivial things like multiplicantion, division, etc, but when any kind of mathematics is involved ( there was an interesting thread called mathematics=arithmetic which had a good discussion about the distiction between the two fields), I use it. Also, for important formulas like the quadratic equation I find its a good idea to use it as much as possible instead of just graphing it on the calculator. I don't see any reason to do trivial arithmetic though, when the calculator can do it.
  4. Jan 27, 2007 #3

    Gib Z

    User Avatar
    Homework Helper

    I was the only one in my grade to do my entire years worth of math exams without a calculator. I try my hardest to not use it, at every opportunity I use all the Taylor series and Algorithms I know to compute anything, but if I need more than 4 digits accuracy, then I'll use a calculator. These were only Year 9 tests (For Australian 14yr Olds), and most of the answers said to give the answers in exact form, so I had very little computing to do anyway. The only question that said to give to 1 decimal place was easy to do with Cosines Taylor Series, only first 2 terms.

    I topped the grade and got 100%, just proves you don't need a calculator.

    I prefer to use it as little as possible, but in higher grade tests Ill have to.
  5. Jan 27, 2007 #4
    Unless you are a human calculator, you simply won't have the time. Tests are often designed assuming you have a calculator at hand.
  6. Jan 27, 2007 #5
    I generally don't use one, but it depends if im doing things for fun or if im working at something (where i don't have time).

    I mostly use one for Trig functions and Roots, I memorised the first 10 roots of primes to over 8 decimal places and various constants anyway, only roots method i know is the Newton-Raphson method, and its tedious.

    I obviously memorise log tables for the first few primes and first few integers etc and some other shortcuts.

    Im very poor at manipulating digits mentally though. And at 14 i barley knew what a number was, never mind the Taylor series :surprised
  7. Jan 27, 2007 #6
    When I need to find a particular root to a polynomial quickly, and it doesn't factor nicely, I'll go to the calculator. This is especially helpful for any polynomial over the 2nd degree (but typically less than 6th degree). Using it to reduce a matrix to row reduced echelon form is also especially handy. These functions helped in a couple of finance classes where solving for things like IRR, or immunizing a portfolio would be too tedious by hand.

    The higher you go in math, the less important the calculator becomes. I'd guess the calculator is much more important to engineers and business majors than to actual math majors.

    Of course, for calculus, it depends on what your teacher expects of you. Some teachers conduct a class in such a way that a calculator isn't necessary. Others are a little more relaxed. I'd say use your discretion with the calculator. If it's something that's obvious or can easily be done by hand, don't bother. If you get bogged down with computation in a problem, using a calculator could be of benefit.
    Last edited: Jan 27, 2007
  8. Jan 27, 2007 #7
    I like using my caclulator. I know I will make a mistake if I do not use it. My mind works beyond the step i'm doing a lot of times and I confuse numbers. I find that the calculator is a helpful tool. I am not going to sit and waste time by doing calculations that a calculator can do. I rather take the results of those calculations and apply them to the main problem I am working on.

    Besides, what really is the point in not using it. It seems rather elitist. Yes, you can not use it, but i'm not for making things more difficult than they have to be.
  9. Jan 27, 2007 #8


    User Avatar
    Science Advisor
    Homework Helper
    2015 Award

    i don't own one.
  10. Jan 27, 2007 #9


    User Avatar
    Homework Helper
    Education Advisor
    Gold Member

    A reason for NOT using a calculator is the focus on concepts and symbols. Your professor is often looking to assess your understanding of concepts, formulas, and analytical judgements. The professor often wants to see steps in a solution process leading to a symbolic form result. The use of a final numeric result is of no importance there. This goes so far as to assign about 80% of the exercise's credit to the solution process and symbolism; and no credit be permitted for numeric results by themselves.
  11. Jan 27, 2007 #10
    The guy who said that calculator use decreases with advancement in math was absolutely right. I think that starting with high school precalculus, the calculator really starts to lose its usefulness. This isn't to say that it doesn't come in handy. For example, when I need to do calculations in a physics class, such as a polynomial factorization, I have no reservations about going to my TI-89. But I make sure to keep those skills sharp, because in math courses, doing these things by hand greatly increases one's intuitive understanding of the subject material. I use my calculator quite often in physics, but I very rarely use it in math. The only exceptions were classes like numerical analysis and computational algebraic geometry, in which the subject matter required the use of a computer (which I suppose is a calculator too).

    The only thing I really need a calculator for is simple arithmetic. Throughout my college career, I was never good at directly doing arithmetic with numbers. Heck, it wasn't too long ago that I spent a minute trying to add $1.50 tip to a $9.20 meal. For the longest time I figured that since it's never hurt my grades, why bother learning it. Of course, last summer I finally developed a conscience, and started trying to actually develop this skill. How a person like me wound up with a math degree is one of those great mysteries of the universe!
  12. Jan 27, 2007 #11


    User Avatar
    Homework Helper

    I dunno. I find that simple calculators are fairly useless in advanced pure math, but the sophisticated ones help to relieve some of the burden. Nice to be able to divide two complex numbers (for example) by simply punching them into a calc, since doing it by hand can be tedious and pointless when you already know the concepts.
  13. Jan 27, 2007 #12
    My intentions were not sound elitist, I was curious of the applications of the calculator. I have never learned how to use it properly, so I was wondering if it can help alleviate a lot of work, that one doesn't need to practice.
  14. Jan 27, 2007 #13
    I have a ti-89 that I use to do simple arithmetic, and that is about it (I sometimes mess around with graphs). I have never really needed it since calculus, although I used it a few times in Linear algebra (to do some matrix things), and a time or two in vector and complex analysis. Other than that I rarely use it, I mostly take pure math classes though, so I can't speak for applied people that might use one often, though I would think maple, mathematica, or matlab would be better.
  15. Jan 28, 2007 #14


    User Avatar
    Gold Member

    When my kids ask if anyone has a calculator, I always say "I do.", tap my head, then say "lay it on me".

    They hate that.
  16. Jan 29, 2007 #15

    Gib Z

    User Avatar
    Homework Helper

    Quote somebodysnamewhoicantrememberwho: Tests are designed assuming you have a calculator at hand.

    True, but yr9 tests are amazingly easy, the only calculations that need to be done, if at all, are trig functions to 1 dp, not much.

    Most of the reasons people use them for here, i would too. Its just that they dont pop up in my tests >.<

    I remember the square roots of the first 9 primes (catching up to you dude :p) and im trying to learn more every day. Ill probably stop soon, the vast majority of numbers will be a product of them, or I won't be bothered even if i did know the roots of their factors :p I also remember e, pi, golden ratio etc.

    I try to keep fractional approxs as well, eg pi approx 355/113, e seems like a repeating decimal place (2.718281828) so assuming it goes on with the 1828s we can get a fraction for that. Golden ratio is defined, easy to remember, and subsequent terms of the fibonachi series when divided congerve to it.

    Basically saying, Remember the small things and itll help alot.

    O and mathwonk, of course you don't need a calculator, everyone here knows that :P
  17. Jan 29, 2007 #16
    Just so you know e is irrational, however, a fraction that evaluates to that repeating decimal would probably be a very good approximation since that's already 9 decimal places.
  18. Jan 29, 2007 #17

    Gib Z

    User Avatar
    Homework Helper

    Sorry lol, i didnt mean to give the impression that it was equal to the repeating decimal places thing, just trying to say it looks abit like it when you see it on your calculator. Its also transcendental :p
  19. Jan 29, 2007 #18
    That's alright, I should have figured you knew that, just making sure in case someone else gets confused.
  20. Jan 29, 2007 #19

    Gib Z

    User Avatar
    Homework Helper

    Its all good.

    So basically, to the OP, summing it all up.

    We use it when the calculations are tedious, time wasting and boring, but we try to make sure we could do it without a calculator if required.
  21. Jan 30, 2007 #20
    Okay, that is my approach as well. I seem the be the only pure maths student in my classes. Everyone else likes to punch numbers.
    Last edited: Jan 30, 2007
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?