Casio FX-991CW Scientific Calculator

Esta calculadora tiene todo lo que necesitas en una ingeniería, aunque no tiene gráfica (te da un QR para abrir la función en tu celular) tiene funciones que no vas ni a usar de tantas que son, pero estan ahi. Tiene mas funciones que otras mas costosas. Es la calculadora ideal.

Facil de usar, los menús se entienden, esta muy bien organizado el sistema.

Me encantó las hojas de cálculo que tiene como si fuera excel (es un poco limitado, pero puedes hacer muchas, muchas cosas)

NO te arrepentiras de comprarla
Es una buena inversión

There are three calculators that are of roughly the same price that are solar-powered scientific calculators. They are now the casio fx-991CW (previously the casio fx-991EX), the Sharp EL-W516T, and the TI-36X Pro. The fx-991CW [henceforth CW] is basically a user interface change from the fx-991EX [henceforth EX], with, as far as I can tell, no useful new functions and a slower (although perhaps easier to navigate) interface. The only functional additions are a dice roller and a coin flipper program, neither of much utility for the CW over the EX.

[From my review of the casio EX, though the same applies to the CW for the most part:

All of the calculators are going to work, but the casio [EX] has the highest resolution screen and fastest processor. A definite integral on the casio [EX} is often instant and is at least 5x faster than the same calculation on the TI or Sharp calculators. The casio [EX] calculator also keeps square roots of values more consistently, allowing you to get exact answers. The casio [EX} has all of the features that you’d expect from a scientific calculator except a GCD and LCM calculator. This is not a big deal to me, because the casio [EX} does prime factorization which allows you to get these quite easily, but it is annoying that they didn’t implement them nevertheless.
]

The casio CW still clears the memory of recent calculations whenever you switch modes or the calculator turns off [the same as in the ex], which I find annoying. This means that if you wanted to keep a value for the next time you turn it on, it simply isn’t possible. Again, the same as the ex, the CW answer button is programmed to only keep the last value in the stack. (So if you did 2+1=3, and then put in 2+2=4, then went back to see 2+1=3, and typed +2 (Ans would be inserted for you) you would find 6, not 5.) So if you would like to use a previous result you have to scroll to it and enter it again or edit the equation from there. On a more negative note, the CW has reprogrammed the power of 10 button (commonly e or E button) such that it does not take operator precedence on the number preceding it. This means that if you type in 10/2 and get 5 then hit divide by 1E3 [E corresponding to the x10^[] button, which will show up as Ans÷1×10^3 on screen], you will get 5000 and not .005. This is contrary to the use of the power of 10 button and the ex and every other calculator handles this correctly (that is, it doesn’t just treat the power of 10 button as a regular multiplication).

More generally, the CW is actually noticeably slower than the EX at doing integrals. It’s still fast compared to the sharp and TI counterparts, but no longer as outstanding. The CW has also done a total keyboard layout change, and relegated many functions to the catalog button. I can live with such changes, though it takes several more button presses to achieve results. The format key is somewhat annoying because you can no longer default to engineering format, but it is at least straightforward. The buttons themselves are nicely put together at least, and I actually like the more subdued look of the CW compared to the EX.

Overall, any of the calculators will work, but the casio EX is the fastest with the CW having the best looking screen. I prefer the EX over the CW, but either is faster than the TI36X Pro or Sharp EL-2516T. If you have an EX, I’d say stick with it, as it has all the same functionality (with the bonus of implementing the power of 10 button correctly). A TI36X Pro is probably now the best bet if the power of 10 is make or break for you and you cannot get a reasonably priced EX.

Muy buena calculadora, tiene grandes funciones y es perfecta para la carrera universitaria

I ordered this for my college student and he loves it. It ahs all the functions he needs, easy to work with and works great every time.

カシオの関数電卓CLASSWIZの最新機で日本版のfx-JP900CWのグローバル版ということらしい．
先代機のfx-991EX（fX-JP900-Nのグローバル版）は愛用しているが，持ち運び用とデスク常備用で使い分けようと思い購入．

結論として「関数電卓としては」少し残念な仕様変更になっている．

デザインは主に記号入力ボタンの白印字とそれに対応したSIFTと組み合わせる「裏入力」表示のゴールドのツートーンがシンプルで，何を押せばいいのかが直感的によりわかりやすくなっているのがいい．
logボタンの表裏は日本版と逆になっているようだ．
これは好みや使い方の問題だろうが,個人的には「底を指定のlog」が表で，裏に自然対数や常用対数となっているこの海外版の仕様のほうが好みだ．（なぜって底が揃っていない計算の方が面倒だから電卓の出番が多い．）
速度や計算精度は概ね強化されているのも良い点．（シンプルな関数の定積分なら割と早い．カシオやHPの上位機種のグラフ電卓には流石に敵わないが．）

残念だと思う先代からの変更点はS⇔Dボタンが無くなったこと．計算結果の表示を分数や小数で切り替えるのがFORMATボタンから上下カーソルで選択式になって手間が増えたのが地味に不便．（10桁までの整数なら素因数分解ができるがそれはちょっと嬉しい．）
また定積分がボタンで一発で呼び出せず操作盤のどこにも積分記号がないのが混乱する．（これはCATALOGからFunc Analysisを呼び出してさらにIntegrationを選択しなくてはならなくなった．）

性能は確かに強化されているが，おそらく多くのエンジニアにも他の理系の人にもUIは不便になったと思われる．
ボタンが見やすくなったのは助かるが，UI周りの仕様で関数電卓を普通の電卓ユーザーのニーズに寄せなくてもいいと感じた．

よく使う計算はすぐに操作は覚えられたが，その大半で先代機よりわずかに手間がかかる．
普段遣いは結局先代機になりそうだ．

Excelente calculadora, tiene demasiadas funciones lo malo es que todavía no me aprendo todas para sacarle máximo provecho pero esta bien, viene con cosas útiles como convertir de una medida a otra, simbolos, cuenta con carga solar y creo ya trae pila incluida porque no la he puesto al sol y funciona, cuando me llego prendía y hasta la vez prende. Producto 10/10. Si no te sirve ahorita al 100% en un futuro si la cuidas bien puede seguir como nueva y ahora si sacarle provecho pero creo que es un producto orientado a universitarios o si van en preparatoria.