Tired of spending as much as a tablet on each Texas Instruments 84 Plus calculator? Casio’s answer is the Classwiz fx-991EX, a calculator that exudes power and abilities, but does so on a tight budget. It’s not only smaller and lighter, but at $20 is a genuine bargain. It may lack the 84 Plus’s color screen, but the fx991EX calculator has a better idea on how to inexpensively graph functions.
At 0.5- by 3.0- by 6.4-inches the white and black calculator weighs 3.2-ounces, less than half as much as the super-sized TI Nspire CX, and squeezes a lot of calculator into a small package. It comes with a slide-on cover and has a nice textured finish, but has plastic feet instead of soft rubber ones. Its keys are thoughtfully color-coded with chromed on-off, Menu and shift buttons as well as arrow keys.
The 2.4-inch screen shows a lot more detail than other calculators, but is limited to black and white characters. It uses Casio’s Natural Textbook Display that can show six lines of calculations and looks like printed material, although sometimes the characters are oddly out of proportion with each other. It can display up to 15 digits for basic calculations or 10 base numbers and 2 for scientific notation. My favorite is the dedicated scientific notation key in the bottom row of keys that can help make quick work of physics and chemistry calculations.
You can either use its Calculation Mode that has icons for 12 different math activities or dive right in. The calculator has nine levels of memory, the ability to work with 160 statistical data entries and a random number generator. Made a mistake? There’s an undo key.
Either way, the fx991EX has more than 500 mathematical abilities at its disposal that range from the expected trigonometric functions to directly inputting fractions. It comes into its own by solving 4x4 matrices, heavy-duty statistical problems and simultaneous as well as differential equations. It can perform numerical integration and even solve hyperbolic curves.
The calculator can work with large spreadsheets that have up to 5 rows by 45 columns of data and deal with 70 data points at a time. In other words, it’s a great tool for completing STEM work and labs. The fx991EX contains 47 important physical constants and can convert major English and metric units.
It may not be able to directly graph equations, but the fx991EX adds a new idea that can change the calculator dynamic in schools. Rather than drawing graphs on its screen, the calculator can create a QR code that links to an equation’s graph online. All you do is press the QR key and the screen creates and shows the distinctive square code. Then, click a shot of it with a phone or tablet using the QR scanning software. The system is taken to an online place that displays the graph in color, perfect for showing the class with a projector or cutting and pasting into homework.
Rather than disposable or rechargeable batteries, the fx991EX can be self-powered with a two-way solar panel above its display. When it’s charging the system’s batteries, a small sun-like dot appears in the screen’s upper right corner. This panel powers it just as well in natural daylight or by classroom fluorescent lighting. In fact, unlike its competitors, it doesn’t have a charging port or come with an AC adapter or cable.
The only downside of it being self-powered is that after 10 minutes of inactivity, the screen goes blanks and the calculator goes to sleep. It will eventually need to have its LR44 watch battery replaced, but that’s a couple of years in the future.
While TI has a plethora of printed and online help, lesson plans and an army of teachers who can explain how to do the simplest or most complex operations, Casio includes only a skimpy 44-page User’s Guide. Online, Casio has lesson plans and other educational resources for algebra, statistics, geometry and calculus, but nothing specifically for the recetnly added fx991EX.
While it’s not available yet, the calculator will soon have a software emulator. This should allow a teacher to show the entire class how to do complicated key sequences on a notebook connected to a projector.
The bottom line is clear: rather than spending roughly $3,000 per class for high-end graphing calculators, Casio can equip it for something closer to $600. And, that’s the best math lesson any school can learn.
Casio Classwiz fx-991EX
+ Solar powered
+ Small and light
+ Can use QR codes for creating online graphs
+ Comfortable keypad
+ Lots of calculations and functions
- No on-screen graphing
- Light on curriculum