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8 Reviews

Type: Calculator

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    8 Reviews
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    • More +
      09.02.2011 00:10
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      nice choice of calculator

      I switched to this calculator because my university told me I had to. I am very glad they did. This is so much simpler and easy to use than other scientific calculators I have used in the past.

      Although it isn't really important, I really like the fact this is a brightly coloured calculator. Mostly they're black or dark grey and ever so dreary. This cream and pastel coloured calculator really brightens up maths! (well, a little bit)

      The solar panels aren't a feature of many scientific calculator, but they really are handy. The tiny batteries needed are so hard to find, and even harder to change that I've just thrown away calculators in the past when the power runs out. The solar panel on this calculator means I don't have to worry about that anymore.

      My favourite thing about this calculator is the fact that the case contains a few notes on how to carry out functions such as change the mode and carry out simple statistical tests. These do not violate exam regulations in my university (which is a highly prestige member of the russell group) so I don't think many places will have a problem with them. I've found they get me out tricky situations time and again.

      This calculator is a bit cheaper than many similar products on the market. I can only assume they can afford the lower price due to the popularity of the calculator, because everything seems to be of very high quality.

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      09.09.2010 16:38
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      good calculator for the maths conniseur

      the mother of all student calculators. i first seen this model when my friend borrowed it off his dad, and the first thing i was drawn to was the integration button. although it only solves definate and rational integration, it is still a massive boost to any maths or physics students arsenal, shaving you from wasted minutes in an exam using your basic on-paper method. one problem, however, is that they have placed the new integration button where the old magnitude button used to be on the older casio models. this makes the calculator more favoured towards the pure maths and statistics area, rather than the physics and mechanics students, to whom the magnitude button is a necessity.
      Aside from the integration button, it behaves like a normal casio. As always, this casio provides a very easy to use and navigate statistics option, with the ability to call up an F(x) table t the touch of a button, and also has a variety of useful formulas that can be applied to the table, such as variance and SD to name a few. the natural display is much easier to work with than the old linear disply, as now you can enter formulae just as they appear on the page, and it is all displayed infront of you, with no unnecessary scrolling back and front to find that one misplaced symbol. Getting off the complicated stuff on to the basics, the solar panel provides reliable battery life, so no worrying about it dying in the middle of an exam, and the ergonomic shape fits perfectly into your hand. the sliding cover is useful also, as on the inside it contins some basic instructions about how to access specific functions on the calculator, in a simple button by button way. the silver look is also a bonus in my books, because the other casios are all some drab blue colour, and this way people know you've bought the upgrade model;)

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      05.08.2010 16:04
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      recommended

      For my maths exams my maths teacher told me that I needed to use a proper mathematical calculator that was more advanced than your average one, meaning it has more numbers and different functions on it.
      We already had a scientific calculator hanging about the house and that was this one, the Casio FX 991ES. I took it to school and my maths teacher said it would be alright to us this one.

      The numbers on this calculator are at the bottom of it. Near these numbers you get all your basic functions, such as x, divide, + and -. You also get =, Ans (which you press to get the answer from the last calculation you did if you accidentally delete it before you see it, or you press it to use the the answer from your last calculation in another new equation), . (decimal places) and one that isn't so basic, x10 to the power of x.

      With this calculator it is great for saving the battery life because of the darkness sensor at the top which turns the calculator off on its own if it is left in darkness or you put your finger over it. Also it will go off if you leave it without touching it for a long time and it isn't in use.

      The calculator is almost 8cm wide and it is around 16cm long. I just measured it then, but these are only approximates because I had to use a dodgy protractor to do it lol. The calculator fits comfortably in your hand and it is very easy to use. The buttons are pressed very easily and I have never experienced any problems with stuck buttons etc.

      Almost everyone in my maths class had a similar version of this calculator or the same one. And it was the kind that my maths teacher recommended, so I think this proves that this is at least one of the best out there, if not the best calculator.
      This is currently £9.59 from amazon. Check if they sell this at your school though if you are looking to buy this for maths in school because my school were selling them for quite reasonable prices.

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        13.06.2010 01:56
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        At £9.81, my calculator tells me you are paying roughly 2.43p for each function of the 991ES

        My maths teacher recommended this calculator for class room use when I started a-levels a few years back, so although I already have a standard Casio Fx 85MS at that time, I ordered one from the maths department office.

        The Casio FX 991ES is, in many ways, much more powerful than the Fx 85MS. It is light in weight and well built and mine coped well with some rather rough handling; the calculator has a double way power (solar/ battery cell), mine has been working for the past few years never needing a change of battery. It claims to have 403 functions as compared to the 240 of the 85MS, and there are many features which I found extremely useful but missing on the 85MS:

        I love the bigger screen. The natural textbook display makes full use of the screen and shows formulations the way they should look like in real life, an absolute dream when you compare it to a single line formula display of the 85MS, because errors can be spotted much easier, specially with fractions and brackets; but I didn't like the colour of the display, I found blue against green to be a poor choice and doesn't look as sharp as black against greyish green on the 85MS.

        The layout and the size of the buttons are in similar style as the 85MS, but do be very caution because some buttons are reshuffled! It took me ages to find the nCr button which had its specific button on the 85MS, only to find it to be hidden away as Shift X on the 991ES! Other functions such as equation solving, numerical integration and differentiation, and multiple input statistics have also been very useful for my a-level course. And the additional scientific constants list (Shift 7) has some commonly used constants for most physical chemistry and maths calculations, such as Planck's and Avogadro's.

        Retail price starts at roughly 10 pounds, which is absolutely value for money for such a powerful scientific calculator with 15 digit accuracy. I do understand all its 403 functions might not be useful for maybe a housewife who wants to do her budgeting, or for everyday office use; but for a student studying for a maths/ science course beyond GCSE level, I would recommend this product. (Although I did continue using my 85MS because I find it easier to read off the numbers from the darker display, but I do use the 991ES for specific functions)

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      • More +
        10.10.2009 20:32
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        It Is The Best Scientific Calculator

        This is one of the best scientific calculator that you can buy.

        This scientific calculator allowed me to get through maths and stats a levels.

        Without this scientific calculator it would have been really hard to get though my a levels, this scientific calculator can be used by anyone, including lower years or even at GCSE.
        The scientific calculator is very easy to use and has all the buttons is the right place.

        The scientific calculator has many functions that can be use to solve many problems. I love the fact that the scientific calculator use two types of power, one solar and the other battery. As this way it means that you are safe to take it into an exam without it failing not to work.

        I have recommended this scientific calculator to all my friends that were on the same course as me, and they all bought it !

        My opinion of the product is that I think that it is one to the best calculator that you can buy, as you are able to use many functions. One of the functions that I use to use a lot was that you are able to save the result that you get and then be able to use the same figure in the next part of the sum, without having to round up numbers or to re-type up the whole digits which can lead to errors.

        Other great functions that I used was that you are able to use the calucator to work back wards, such as in algebraic equations. This can make life so much easier.

        The numbers that are displayed on the calculator is really easy to read as they are a large font size. Another great thing with this calculator compared to others is that you can display many digits on the screen, as once you go over the 16 digits and arrow comes up that you able to press to see other digits and continue pressing digits.

        In terms of memory all that I know of is that there are around 7 spaces in which you are able to store your own data (your own numbers).
        Other functions in the calculator are the use of the stats mode, matrix (have not used this), vector mode.

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          02.07.2009 16:22
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          Probably the best calculator on the market, despite some problems.

          I bought this calculator just over a year ago with the intention of using it in exams, specifically A levels. I was a little worried it would not be allowed at first, because as other reviewers have noted, it is a very powerful calculator, however the only rule set by the JCQ (who regulate A levels, GCSEs and some vocational exams) is that the calculator must not be capable of symbolic calculus (note that this may change in time, but for my session was accurate).

          However, this calculator is still very powerful. It provides far more functionality than the average user would need. This includes numerical integration and differentiation, which if used by someone who knows what they are doing, is as useful as symbolic calculus, as a confirmation.

          This is also the main disadvantage of the calculator - for all it is capable of, the old computer adage of Garbage In, Garbage Out still applies. The end user needs to understand the maths behind what they are doing, and the calculator offers no functionality to assist this in any way.

          The other major problem is a "lag" in long calculations. For example, in large fractions, possibly including summations (sigma), the screen redraws itself after every input, and will not accept any other input in this time. This means that if you are trying to type 222, then the last 2 might be missed, causing the result to be out by an order of magnitude. This is a problem that has cost me marks, and so when using the calculator it becomes vital to double-check calculations.

          One final problem is mainly caused by the calculator's other function. When typing a calculation such as the square root of 8 or 2pi, the calculator is knowledgeable enough to display these in standard form - 2(square root sign)2 and 2pi respectively - this is the form that is most useful for a mathematician. However, it does not extend this functionality to any logarithms (the calculator can do any base of logs) or exponentials, displaying these as decimals. This is particularly a problem in advanced calculus where it is more useful to have the natural logarithm function.

          In conclusion, despite a number of problems, there is no doubt that this is an excellent calculator. GCSE students thinking of taking any A level mathematical subjects (which includes the sciences) would be well advised to purchase this, probably in addition to a graphical calculator. Physicists might also find its database of constants useful. However, for other students, cheaper alternatives might serve them better, and for an average end user just interested in calculating VAT, this is not a suitable calculator.

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          • More +
            03.06.2009 17:55
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            Don't go for anything else

            This is an unbelievable calculator and at £8.41 on amazon.co.uk is definitely worth buying if you are sitting any form of maths exam above gcse standard. Firstly when buying a calculator it is important to not get carried away when buying a calculator with a lot of functions just because it has them. However this calculator has a lot of functions which always makes me question how it ever came to be allowed in exams.

            Besides the basic functions that you would expect from a calculator I have used this for several things all of which are extremely helpful in an a level maths exam. Firstly it will do all sorts of numeric integration, which is great for checking your answers. Next it has a function which solves linear simultaneous equations with 2 or 3 variables and also polynomials up to degree 3. This function is a fantastically quick way to factorise long polynomials without losing any marks on a paper.

            Next there is a more general solve solution which although it does not always work, has an uncanny knack of solving equations very quickly which again is great for checking your answers. Finally if you take something like further maths then this calculator will also work with complex numbers and has a vector mode which is handy for laborious vector product calculations.

            In short, this is unlikely to add too many raw marks to your maths exams (though it probably still adds around 10%) however the ability to check the majority of your answers with confidence during the exam is a fantastic help to both marks and confidence. Definitely worth buying for a level maths!

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              19.05.2009 17:38
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              An must-buy for university or advanced level mathematics

              This is an extremely comprehensive calculator that contains a huge range of mathematical functions, and is only short of graphics capability.

              In addition to the normal scientific calculator functions, this model has many notable features and modes. It has a complex mode that supports all basic mathematics on the complex numbers, and is intelligent enough to know that i^2 = -1. When working in the real numbers, the calculator is able to solve equations with one unknown variable.

              For users in the physical sciences, the calculator has a bank of 40 constants, such as the Gravitational Constant and Avogadro's Number. There are also 40 base conversion, but these seem altogether less useful.

              The calculator has a useful matrix processing function, which is able to calculate the determinant, dot product and scalar product of vectors up to 3x3 in size.

              Casio's natural display is the default interface for this calculator and its realistic portrayal of notation is particularly enjoyable for roots and fractions, which are automatically simplified.

              A useful final thought is that the calculator does not have a graphical function or textual memory, which means it is eligible for many university examinations, despite its power functionality.

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            • Product Details

              Scientific calculator with 403 functions and natural textbook. With advanced mathematical functionality.