CATIGA Black Scientific Calculator with Textbook-Style HD Display, Solar & Battery Scientific Calculators for College, High School & Engineering Students, Icon Menu & Magnetic Hard Case, CS-991NX
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Availability:
Only 10 left in stock, order soon!
Arrives
Saturday, Aug 22
Color: Black
Features
- TEXTBOOK-STYLE HD DISPLAY - SEE MATH THE WAY IT'S WRITTEN: A crisp high-resolution screen with 4-gradation shading shows fractions, roots, exponents and equations exactly as they appear in your textbook, not squeezed onto one flat line. An intuitive icon menu switches between Calculate, Statistics, Distribution, Spreadsheet, Table and Equation modes in one tap, so input is faster and mistakes are easier to catch
- 538 FUNCTIONS - EVERY TOOL FOR EVERY COURSE: One scientific calculator covers General Math and Pre-Algebra through Algebra, Geometry, Trigonometry, Statistics and Calculus, plus Physics, Chemistry and Engineering. Handles matrices and vectors, complex numbers, equation and inequality solving, a built-in spreadsheet, statistics with regression and distributions, base-n, prime factorization, 47 scientific constants and 40 units conversions, you never need a second device as your classes get harder
- MAGNETIC HARD CASE INCLUDED - PROTECTION THAT STAYS ON: Unlike calculators that ship with a flimsy slide-on cover, the CS-991NX comes with a rigid magnetic snap-on hard case. It clicks securely into place, survives being tossed in a backpack or pencil case, and won't slip off - so your calculator stays exam-ready year after year
- DUAL SOLAR + BATTERY POWER - NEVER DIES MID-EXAM: This solar calculator runs on light whenever it's available, with battery backup for everything else. No surprise shutdowns during a test, no scrambling for a replacement battery the night before an exam
Description
This is my first scientific calculator, how hard is it to learn? Most scientific calculators share the same underlying logic. Once you understand the core concepts, switching between models is easy — the icon-menu layout here makes that transition even smoother. I need this to last through several years of school. Is it durable? Yes. The casing and keys are built to hold up to daily use — tossed in a backpack, pulled out between classes, used every day for years. Can it handle statistics and table-based problems, not just basic arithmetic? Yes. It includes dedicated statistics and table modes for regression, data analysis and function tables, on top of standard scientific calculations. How long does the battery last, and what if I run low mid-exam? It runs on dual power — as long as there's reasonable light it keeps working even if the battery is low. Is this calculator suitable for exam prep? It's built to support the full range of practice you'll do while preparing. As with any calculator, permitted equipment varies by exam board, so check your specific exam's guidelines as part of your prep.
Brand: CATIGA
Color: Black
Calculator Type: Engineering/Scientific
Power Source: Solar and Battery Powered
Number of Batteries: 1 Nonstandard Battery batteries required. (included)
Brand: CATIGA
Model Name: CS-991NX
UPC: 810185461714
Manufacturer: CATIGA
Number of Items: 1
Model Number: CS-991NX
Mfr Part Number: 991NX
Warranty Description: 1-Year Limited Manufacturer’s Warranty
Calculator Type: Engineering/Scientific
Power Source: Solar and Battery Powered
Number of Batteries: 1 Nonstandard Battery batteries required. (included)
Display Type: LCD
Color: Black
Item Dimensions L x W: 6.5"L x 3.25"W
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Saturday, Aug 22
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Purchased for grandchildren to use at school. Functionality good for them. Purchased reasonably .
Reviewed in the United States on May 4, 2026 by ct
This reasonably-priced calculator is perfect for use in Algebra I class!
Reviewed in the United States on December 4, 2024 by Amazon Customer
Grandson broke his other calculator. Needed replacement but didn't need to be graphing. This one fit the bill. Does same steps.
Reviewed in the United States on November 28, 2023 by Vicki M. Miller
Color: Blue
CATIGA Blue Scientific Calculator with Textbook-Style HD Display, Solar & Battery Scientific Calculators for College, High School & Engineering Students, Icon Menu & Magnetic Hard Case, CS-991NX I didn't realize it at first, because I'm more into Casio watches, than calculators, but this is a nearly identical clone of a Casio fx-991CW. Now, I'm not sure if the design was officially licensed from Casio or not. However, there is nothing written on the box, calc, or manual mentioning it. If this was a legal design licence or rebranding, there would always be a notice. The firmware operates identically to what is in the Casio fx-991CW, even down to having that novelty MathBox menu with the coin toss & dice roll. That CANNOT be coincidence. This is absolutely Casio's firmware, possibly with minor mods. As a clone, the Catiga is pretty much spot on a 99.9% duplicate, with the minor exception of the keypad layout being slightly rearranged. Oddly enough, depending on wher you shop, you can buy the official Casio version for less money. Go figure. The Casio version of this calculator has already received a ton of great reviews, and so did this clone. I generally just bounce around randomly in the review section of an Amazon listing to see what the primary issues were. The 4ward Thinker says... " I have been having the hardest time trying to figure out how to remove this square root symbol and the other symbol next to it at the top left of the screen. . I believe that these two symbols are interfering with the outputs of basic math problems." ---> It's on page nine of the manual. I found this after less than 30 seconds of browsing starting from page 1. It's just a display choice between showing the answer as a fraction or as a decimal value. Seriously, just go to PAGE 9 and it even shows you screenshots of each step of changing the setting. Did you even TRY to read anything in the manual? "If all else fails then I will try to remove the battery for 30 seconds." ---> WOW. Why are you making this so difficult for yourself? Battery removal not needed. Page 7 of manual (top of page) 'How to factory-reset the calculator' Senor Ricardo y Anita says... "I bought it for my son who is in 7 grade and although he liked how easy it is to use it, we were disappointed that in March he was completely spoilt!!!! Very bad investment!" ---> I don't understand. Are you saying that the calculator was a bad investment, or your son was? What does Spoilt mean? Bot HUMAN NOT AI generates... "This calculator is a capable, functional tool that handles advanced mathematical tasks reliably. It represents a practical alternative to standard academic models, provided you accommodate the lighter build quality. It is well-suited for academic environments where cost-effectiveness and feature set are primary considerations." ---> I'm sorry dude, but this is absolutely AI generated review slop. No one really talks like that except AI.
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Reviewed in the United States on August 14, 2026 by Reviewer
I am very impressed with the easy way this calculator works. I bought several through Amazon because I needed one in specific for a special needs child so I could as her great grandmother assist with her math. She is not able to use this due to her needs but I can now help her. Impressed
Reviewed in the United States on April 6, 2020 by Patricia Niedercorn
Color: Blue
This calculator arrived quickly and in excellent condition. This calculator basically mimics another name brand calculator at a reduced price point. The calculator itself is extremely light, likely not using quite as many resources nor being quite as durable as the name brand product. As the menu on the home page seemed to suggest graphing capability, I was a bit depressed to find out it can only show some graphics, more associated with distribution and spreadsheets. This calculator is also not programmable, so you'll have to find your equation within the database and then enter your variables. It has been a while since I was deep into mathematics, so the vast majority of functions on this calculator we'll likely never see the light of day. The high-resolution screen is not touch sensitive, so virtually everything is going to be found using the arrow buttons and the OK button. I have only used this calculator for a couple of weeks now, but as I understand it, the battery on board this calculator is not rechargeable, but must be installed to allow use of the solar panels. It is a bit unfortunate we did not receive a rechargeable battery with the capability of using solar power to do so, but at this price point, I am not surprised. The cover does a good job of magnetically connecting on the base of the calculator and manually clipping on the top of the calculator. It is also odd that they chose not to make the on button an off button, as well. Instead, you need to use the shift and the AC button to actually shut this unit off. Again, this is not very intuitive and another minor annoyance. Overall, for a price of around $30, this is certainly a very capable calculator with just the issue of finding the functions that you want within menus and sub menus. As long as you understand the limitations of this calculator, I do believe it to be an excellent value.
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Reviewed in the United States on August 10, 2026 by C. O.
So. Needed it for school and it works great!
Reviewed in the United States on May 26, 2023 by Amazon Customer
Color: Blue
This calculator is good in parts and not so good in others. The good parts are that it can handle just about anything and, once you've overcome the complications of setting it up, it will calculate what you want to. I like that the settings allow you to decide how the result is presented, with how many decimal places, and you can decide if trigonometry calculations are presented in decimal values or as square roots (a handy feature for understanding the derivation of these numbers). There are no graphs presented in this model. There are an abundant number of keys which are responsive and don't require heavy fingers. On the other hand, its appearance could be daunting to a student who is not familiar with all the settings and mathematical values. So who is it for? A maths genius of any young age will enjoy it for a while, until they get bored, but it will teach them a lot before they reach that point because it has so many equations and trigonemtrical expressions to play around with. It is not very useful as an ordinary calculator because there are just too many settings, too many ways to get the settings wrong, and it has a pretty dreary monochrome display that looks like it belongs in the 1980s. The contrast can be changed in the settings, but it makes little difference in practice because the numbers presented are very small: they occupy only the small corners of the screen. It apparently handles sunlight with a small solar cell to provide power, but this doesn't charge the battery! It is still powered by a conventional pill-like battery that eventually has to be replaced, and the solar cell is reduced to a gimmick because it doesn't work when the battery is depleted. As a calculator for an advanced student who has to handle sines and cosines and tangents and strings of numerical calculations it's just about acceptable, and I would suggest it might be worthwhile to use this before deciding on a more suitable calculator for your child. To be perfectly honest, I was hoping for a simpler calculator that presented better, using more of the screen but, like so many of us in this present age, my expectations have been spoiled by smart phone screens and calculator apps. Value for money? No I don't feel it is, and it pays to shop around and try some out in a retail store. Useful as a standby, as a spare or until you get a better one, quite possibly yes. Be prepared for a long read of the very detailed instruction book.
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Reviewed in the United States on August 13, 2026 by Graham