Amazing calculator with many functions and fast calculation speed. The only drawback is the screen, which has a problem with the viewing angle. Otherwise, it is perfect for its price.

It is easy for someone to buy it if, for example, they make financial calculations such as interest rates - just be careful with the manual!!!

The very important mod operation that gives the remainder of the division is missing. For computer science students who will deal with cryptography and encoding, the mod operation is absolutely necessary.

Plenty of features, satisfactorily good, I bought it for the exams of the electrical engineering department.

This particular product was mainly purchased for academic use. Studying in an engineering school requires the use of calculations for large expressions, difficult computations, and various conversions. The laptop is suitable for all kinds of use, but mainly professional/scientific. It provides a plethora of capabilities (from calculations of complex numbers and matrix operations to the use of binary system and rough graphic representation). For someone who wants to utilize even a little bit of its full potential, they should thoroughly read the manual. In terms of construction, it is made of good quality plastic with a nice paint job and glossy textures to prevent sweating of the hand. I have been using it for a year now during exam periods and for assignments in various courses. I highly recommend it to students of science-related studies, professors, and academics.

Use as a Computer and Telecommunications Engineer. I will say it very simply. It is the most feature-rich machine you can buy. It is aimed at someone who wants to simply get the best, in the sense of having all possible capabilities. It performs 500+ different functions. There is also the 991es Plus, but this is essentially the newer version of that. There is nothing better to buy, I say this after endless hours of research. If you want something more, then you will have to go for the so-called "programmable" ones, which are indeed more customizable, but they belong to a different category.

Very good, it has several functions that have helped me in university. Fast calculations and most importantly reliable. The price could be better though.

I bought this specific calculator for my school (Electrical Engineering, AUTH) and it has been extremely helpful. It has many functions (including matrices up to 4x4, complex numbers in algebraic and polar form, solving equations (and inequalities!) up to 4th degree (including complex solutions), etc.) which make your life a little easier in order to get your degree. I highly recommend it.
*You can search on YouTube for the video (somewhere around 1-1.5 hours) that explains most of the functions of the calculator.

Awesome calculator, so far it hasn't disappointed me and it does more than what a student might need. The only thing that might bother me is how the buttons shake, I feel like I could press them faster but that stops me

Extremely good device for its price. A must-have for every student of science and engineering fields, useful even for professionals.

I bought it for an exam at the Department of Electrical and Computer Engineering at Aristotle University of Thessaloniki. Do not choose it under any circumstances!!! It causes continuous irritation, makes me want to hit my head against the wall, and anyone I know who has chosen it is considering going to a psychologist!!! Of course, I am talking about the Department of Electrical and Computer Engineering at Aristotle University of Thessaloniki, the little computer tool that does it all!

It is ready to use (it already has the LR44 battery).
It was purchased for school exercises in the field of positive sciences and I am very satisfied with its capabilities.

Excellent, of course with all that it has, it takes a whole day to learn it but it is a real tool, it has solved my hands.

Excellent little computer, perfectly meets the requirements for exams in a math school. User-friendly with satisfactory build quality.

Truly one of the best calculators for the money. I bought it 3 years ago for use in my school class and since then I realized the difference from the others I had. It can solve up to 4x4 matrices, functions, etc. that you can find on the product's website. Its great advantage is the solar panel it has, I have been using it almost every day for so long and I haven't had to change the battery yet. Even the slightest light in the room is enough. The quality of the materials is quite good and it has remained like new. I highly recommend it to anyone studying in science schools because it excels compared to regular calculators in correcting operations and provides many additional capabilities.

I give it 3 stars because compared to the 991DEX, it has fewer capabilities when pressing ALPHA. For example, it does not calculate the Modulo (remainder of a division), which I consider essential for such a calculator.

It can do almost anything a non-specialized person needs. Complex fractions with expressions, statistics, matrices, and integrals. Almost everything on one functional screen. It can operate with a battery or with light.
I don't give it a perfect score because it seems cheaply made, both the calculator itself and the cover that protects it when closed, which makes it look like a child's toy. I acknowledge that money is limited, but Casio could have a model with the same features and a higher quality casing at a higher price so that someone can choose. (maybe all this sounds a bit strange, but it's because I've been using the HP 17BII until now and I've gotten used to it)

The most powerful scientific calculator by Casio. Beautiful design, countless functions, fast and with a clear screen. Definitely worth every penny as its price is very good.