What is the difference between the Casio FX‑991ES and 991ex? Which one should I prefer for my VTU exams? - Quora
Which scientific calculator is better for mechanical engineers, a Casio FX-991ES, a Texas instruments TI-36 X or a Casio FX115 ES? - Quora
![CASIO CLASSWIZ FX 991 EX SCIENTIFIC CALCULATOR by ESHUN KWESI APPIAH BUSINESS SOLUTIONS, Made in Ghana CASIO CLASSWIZ FX 991 EX SCIENTIFIC CALCULATOR by ESHUN KWESI APPIAH BUSINESS SOLUTIONS, Made in Ghana](https://img.tradeford.com/pimages/l/9/984409.jpg)