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📚 Calculate smarter, not harder — your ultimate study sidekick!
The OSALO OS-991ES Plus 2nd Edition is a professional-grade scientific calculator featuring 417 functions including algebra, statistics, and calculus. It offers a 2-line written display for easy input verification, adjustable screen brightness to reduce eye fatigue, and dual solar-battery power for reliable use. Lightweight and portable with a durable slide-on case, it’s designed to support students from middle school through college in mastering complex calculations with confidence.
| ASIN | B0CJLC75XS |
| Best Sellers Rank | 11,509 in Stationery & Office Supplies ( See Top 100 in Stationery & Office Supplies ) 23 in Scientific Calculators |
| Brand | OSALO |
| Brand Name | OSALO |
| Calculator Type | Engineering/Scientific |
| Colour | black |
| Country of Origin | China |
| Customer Reviews | 4.5 out of 5 stars 751 Reviews |
| Display Type | LCD |
| Enclosure Material | Plastic |
| Item Dimensions L x W | 16.4L x 1.7W centimetres |
| Item Weight | 0.15 Kilograms |
| Manufacturer | OSALO |
| Manufacturer Part Number | OSALO CO.,LTD. |
| Model Name | OS 991ES Plus 2nd Edition |
| Model Number | OS-991ES PLUS II |
| Number of Batteries | 1 LR44 batteries required. (included) |
| Number of batteries | 1 LR44 batteries required. (included) |
| Power Source | Battery & Solar |
| Power source | Battery & Solar |
| Screen Size | 6 |
| Screen size | 6 |
| UPC | 730637240479 |
F**D
Good Calculator
A simple and easy to use product which does the job for my daughter who has just started secondary school. I would recommend this for anyone else.
M**E
Does exactly what you want it to do
Sturdy calculator. Doesnt feel cheap or anything which is great. Its very easy to use. Didnt take little getting used to but the instruction of the buttons on the inside of the case do massively help. Took this into my Level 2 Electrical exam and passed being able to comfortable answer all questions that had equations. Highly recommend
P**X
Cheaper than Casio but does the same
Casio is the brand but it was about £10 more than this one and so far (last 6 months) this has functioned perfectly well and no issues at all. Definitely good value for money. Hope that helps.
J**H
Quality & Useful
Very Good
G**4
Amazing calculator
Very useful for my son's exam this year.
M**R
Scientific calculator
My daughter used this for her maths exam she said it was perfect.
T**R
It's not what it looks like. Not suitable for A-Level.
At first glance, you might expect this calculator to be a clone of the discontinued Casio fx-991EX. It has the same white casing, the same black, blue and white buttons, and a broadly similar key layout. However, you will see from the photograph that the Osalo has a text interface rather like the old fx-991ES model from 2010, whereas the fx-991EX has a modern icon-based menu. This calculator is a capable enough machine for GCSE or iGCSE Mathematics, but lacks a couple of features now essential for A-Level exams. Foremost among these omissions is a Distribution Function, so there is no way to calculate Normal probabilities without using tables, and for Binomial or Poisson probabilities you have to rely on longhand methods. As for Inverse ("lookup") probabilities, you've got nothing. There is no Spreadsheet function, no Ratio tool, and no Inequality solver, although these would be considered useful rather than essential in an A-Level exam. Some of the other functions have limitations. The Simultaneous Equation solver can solve up to 3 unknowns (Casio 4 Unknowns). The Polynomial Solver can manage up to Degree 3 (Casio Degree 4). Matrix Mode can handle up to 3 Matrices (Casio 4), and each of these is limited to 3x3 (Casio 4 x 4). A brief test of its functions shows that it otherwise works fine and with quick results. The stored constants are all only accurate to about 5 s.f. so use the more official figures if you are calculating with these, or else be sure to round your answers. Overall, fine for GCSE Higher Tier, but go for the new 991CW or CG50 if you need something more suited to Maths A-Level or GCSE Statistics.
S**A
All great
All great
V**I
Comoda
Calcolatrice motlo comda ed utile per mio figlio che fa le superiori.
A**Y
Top
erfüllt seinen zweck Top !!!
C**O
Perfecta
Es estupenda. Muy buena compra
U**A
GREAT
AMAZING, Works too fine
T**A
Sehr zu empfehlen
Der beste Taschenrechner den es für diesen Preis gibt.Meine Kinder sind begeistert.Er kann alles!!Sehr zu empfehlen
Trustpilot
2 weeks ago
2 weeks ago