Got ahold of a Casio fx-991ex and CG-50 to match my Classpad II. I'm really impressed with them but there is something about the fx-991ex... (see comments) : r/calculators
Calculator Tutor for Casio fx-991ES/Plus. For the use in Senior High Schools - GRIN
How to save value in Calculator in fx 991es plus/ The Calculator King - YouTube
fx-991EX Classwiz: Solving Equations and Visualization with Scientific Calculator - YouTube
Amazon.com : Casio FX-991EX Engineering/Scientific Calculator, Black, 3" x 6.5" x 0.4" : Office Products
NEW Casio FX991EX Classwiz Scientific Calculator - Black | eBay
Casio Classwiz fx-991EX - Storing and Recalling Values | Casio Calculator Store Function fx-570EX - YouTube
Amazon.com : Casio FX-991ES Plus Scientific Calculator Fx 991 Es - New & Sealed ship to world wide : Office Products