The product is good value Read more

As a former Head of Mathematics, and a user of Casio calculators for over 40 years, I am confident that the fx-991EX is quite possibly the best classroom calculator they have ever produced. It retains the ease of use of the fx-83GT, but adds power and functionality that takes it literally to game-changing levels. Aimed squarely at the Secondary school market, and carefully featured to ensure that it stays within the parameters of public examination guidelines, this would be the calculator of choice for any student from Year 7 to Year 13 Further Mathematics. The only other calculator an A-Level student might need would be a graphical calculator, but the features of this one make even that an option rather than an essential. Some of the new features that make this compelling for me are as follows: NUMBER The incredibly high definition screen and multi-line display options make it easy to enter calculations and see answers in textbook style and clarity - be they with fractions, brackets, surds (roots), or any combination. The new Random Integer function makes it easy to simulate coin flips, dice rolls and even card selections or lottery draws, opening up possibilities for a huge variety of mathematical experiments and games. Factorising large numbers (up to 10 digits) into powers of prime factors with a single FACT command - amazing. Ratio calculations (example 3:10 is equivalent to ?:7) - the classic ‘Rule of Three’ which was an arithmetic nightmare to Victorian schoolchildren, is now just a tap away. ALGEBRA Incredible power to solve equations and systems of equations or inequalities. The machine will solve algebraically any polynomial equation up to 4th degree (quartics). It can’t go higher because the general 5th power (quintic) is unsolvable - see Galois Theory! However, it can find a root for any general equation using Newton-Raphson to refine a user-supplied initial approximation. Similarly systems of simultaneous equations now go up to four equations in four unknowns. Also, by using the Inequality function on a quadratic, cubic or quartic polynomial, one can quickly find the points on the graph (if any) where it crosses the x-axis. The Solving and Inequality functions alone remove much of the need to turn to graphic calculators when working with graphs of polynomial functions. MATRICES Matrices can now be input up to 4 x 4, with the calculator happily finding determinants, sums, products and even inverses. The previous limit was 3 x 3 matrices, although even this was sufficient to handle most exam questions. STATISTICS This was, for me, the main reason for my purchase. I can now finally dispense with my statistical tables - Binomial, Poisson and even Normal distributions are now covered completely. For example, one can calculate the probability that three coins out of five will show Heads (0.2734375); the probability that a person is taller than two standard deviations from the mean (0.05399096651); a two-tailed 95% Normal confidence interval (+/- 1.959964028) etc. All with a few taps - just entering the values and reading off the result. Note to CASIO - add in Chi-Squared values and you will have all the lab scientists and social scientists queueing up as well! SPREADSHEET Not content with its enhanced Table creation facilities (now supporting two functions f(x) and g(x) rather than just one), a basic Spreadsheet mode is also available, allowing input of formulae with both relative and absolute cell referencing, and display of either results or formulae in each cell. OTHER FUNCTIONS Vectors - including Scalar and Cross Product up to 3-D vectors Calculus - numerical differentiation and integration with user-defined accuracy Complex Numbers - Work with both Modulus/Argument and Cartesian form QR Codes - a QR code is generated by the calculator which can be read by a smartphone and used to display more information about the results via Casio’s own website (for example this might be used to display a graph of the calculator’s results). SUMMARY Razor-sharp display, powerful new functions and the same ease of use in an affordable calculator from one of the world’s most trusted calculator manufacturers make this the most highly recommended product for school use currently on the market. Read more

Boa opção para quem precisa de uma calculadora científica. Read more

Carried me in math, physics, and chem. Read more

Original product and working fine. Read more

A very good product Read more

Тhis calculator is the best choice if you want: - best quality - most features in pocket size - best feature preview Additional: - two types of energy - solar and battery - unique display - intuitive design Read more

Long lasting design. Read more

Product is genuine Read more

Does the job works well Read more

Good Read more

Good product works seamless Read more

Good price and nice quality Read more

Kolay anlaşılabilir ve kullanılabilir, güneş enerjili ve kontrast ayarı güzel iki özellik. Üniversite için iyi bir bilimsel hesap makinesi. Read more

Good price and great product Read more

Aconsejo este artículo Read more

Un excellent produit ! Et cette calculatrice répond aux besoins scientifiques pour les lycéens. Read more

This is an awesome calculator, especially for the price! It has amazing functionality, so much so that I highly recommend reading and understanding the entire manual as there are a lot of details. Read more

Excelente calculadora. Read more

شكرا امازون Read more

Good Read more

Very useful Read more

really good quality and amazing for exams Read more

The Casio Fx-991ES Plus-2nd Edition is an exceptional tool for anyone in need of a reliable and versatile scientific calculator. As a student of engineering, I’ve found this model to be an absolute lifesaver for solving complex problems efficiently. Comprehensive Functionality: It covers everything from basic arithmetic to advanced functions like calculus, matrix operations, and complex numbers. The 417 functions available ensure that it meets the demands of both students and professionals. Natural Textbook Display: The Natural Display makes it incredibly easy to input and review equations as they appear in textbooks. This feature is a huge plus for clarity and error-checking. Durability and Design: The build quality is robust, and the design is sleek and compact. It’s lightweight, making it easy to carry around, yet feels sturdy enough to withstand daily use. User-Friendly Interface: Despite its extensive features, the calculator is intuitive to use. The buttons are responsive, and the layout is logical, making even complex calculations straightforward. Solar and Battery Powered: The dual power source ensures it works seamlessly in different environments, whether you’re under bright classroom lights or in dimly lit settings. Affordable Pricing: Considering its extensive capabilities, the calculator offers fantastic value for money. It’s a worthwhile investment for anyone serious about technical or scientific work. Verdict: The Casio Fx-991ES Plus-2nd Edition has exceeded my expectations. Whether you're a student tackling exams or a professional needing quick, accurate calculations, this calculator is the perfect companion. Highly recommended! Read more

ممتازه جدا جدا واصلية Read more

Es muy funcional para mi hija que estudia la preparatoria ya que le ayuda mucho con sus tareas de física y matemáticas. Además que le servirá para la facultad. Read more

Nice calculator best one yet Read more

If you’re looking into different calculators chances are you’re probably taking advantage STEM classes and your teachers don’t allow graphing calculators or your SAT or ACT may not allow it. Well you’ve come to the right place because this calculator works wonders. I know it might sound odd at first but as someone who’s finishing up an Aerospace Engineering degree I can say that this calculator has come in clutch in more ways than one. Whether you’re solving advanced physics problems, math, or science related problems this calculator has an application. All the different modes that come in this calculator will be able to assist you in many way. It’s easy to use and understand, simply playing will that calculator will show you just how powerful it is. It’s great quality and the value for the price of the calculator is very worth it. Read more

Uso já faz um bom tempo e ela serve pra todo tipo de cálculo que preciso de forma confortável de usar, funções diretas. Read more

Good quality product Read more

Good Read more

A+ Read more

Same as ads Read more

It's really good! I had one like it before, and it lasted with me for 2 years or more, though I don't remember exactly. It will be your best choice!

Good quality, has all basic needed functions Read more

The quality is amazing, solar charging, all advanced options are available. The price also was very reasonable compared to the market. Read more

عملى

زينه

Not good quality. We had returned it but refund not received

good quality works great

Good

Ok

Very good quality and easy to use

This product is original, I had this calculator for 2 years and it did not fail me.

A great calculator for advanced mathematics equations & formulas. Really useful for college/Uni students.

Very good quality as expected

It's like having a math wizard in your pocket, ready to assist you at any moment. The buttons are perfectly arranged and labeled, making it a breeze to navigate through functions and operations. No more fumbling around or getting lost in an ocean of confusing symbols - this calculator keeps it simple and straightforward. It's like having a superhero cape draped over your shoulders, boosting your confidence and turning you into a mathematics virtuoso.Durability-wise, this calculator is a beast. Made with sturdy materials, it can endure accidental drops, backpack jostling, and even the occasional pencil poke without breaking a sweat. It's a trusty companion that will see you through math classes, exams, and countless problem-solving adventures.

I bought this for my son since he needed this for School, and I got better than expected and it was so easy to use and the best thing it works for 2 years and can be charge up with Sunlight

this calculator is pretty great, this thing is gonna last a long time and its functions are very much useful especially for engineering !

Very high quality calculator and responsive, also very sturdy and does not break after a fall, very impressed

Very good product and very helpful in math problems

good

This is simply the best

Bought it in Jan and stopped working in April spontaneously.

مفيدة جداً للثانوي الصراحة استعملتها عشر ايام وجودتها مررررة ممتازة!!!!