[Official CASIO Scientific & Graphing Calculator website] Essential functions for high schools and universities/ Just as textbook display. Manuals > Casio > fx-570ES PLUS > User Manual Casio fx-570ES PLUS, fx-991ES PLUS User Manual. Size: 475.42 Kb. Fx-570ESPLUS fx-991ESPLUS. User’s Guide. CASIO Worldwide Education Website. Do not try using the calculator while the battery is completely dead (fx-991ES PLUS).