1. Úvod
The Casio FX-991MS 2nd Gen is a non-programmable scientific calculator designed for a wide range of mathematical and scientific applications. It features 401 functions and a clear 2-line display, making it suitable for students and professionals. This manual provides essential information for setup, operation, maintenance, and troubleshooting.

Figure 1: Casio FX-991MS 2nd Gen Scientific Calculator.
1.1 Klíčové vlastnosti
- 401 Vestavěné funkce
- 2-Line Display for enhanced readability
- Solar and Battery Dual Power Source
- Multi-Replay Function for formula recall and editing
- Durable, drop-resistant body with water-resistant printing on keys
- Color-coded keys for intuitive operation
1.2 Co je v krabici
- 1 x Casio FX-991MS 2nd Gen Scientific Calculator
- 1 x Uživatelská příručka (tento dokument)
- 1 x Warranty Card with Serial Number
- 1 x Warranty Term Sheet
2. Nastavení
The Casio FX-991MS 2nd Gen calculator is designed for immediate use upon unboxing. It operates on both solar power and a nonstandard battery, ensuring continuous functionality.
Video 1: Konecview of the Casio FX-991MS 2nd Gen Scientific Calculator, demonstrating its features and ready-to-use nature.
2.1 Zdroj napájení
The calculator utilizes a dual power system: solar power for sufficient light conditions and a built-in nonstandard battery for low-light environments or when solar power is insufficient. No initial battery installation is required as the battery is pre-installed.
2.2 Zapnutí/vypnutí
- Zapnutí: Stiskněte tlačítko ON tlačítko.
- Vypnutí: Stiskněte POSUN pak AC (VYPNUTO).
3. Návod k obsluze
The Casio FX-991MS 2nd Gen offers a wide array of functions accessible through its intuitive key layout and 2-line display. The upper line displays the input expression, and the lower line shows the calculation result.

Figure 2: Calculator with its protective hard case.
3.1 Základní výpočty
Enter numbers and operators in sequence. Press = to obtain the result.
- Sčítání/odčítání: Použití + a - klíče.
- Násobení/Dělení: Použití × a ÷ klíče.
- závorky: Použití ( a ) for grouping expressions.
3.2 Vědecké funkce
Access scientific functions using the dedicated keys or by pressing POSUN followed by the desired function key.
- Goniometrické funkce: hřích, cos, opálení a jejich inverzní funkce (POSUN + hřích, atd.).
- Logaritmické funkce: log (základ 10) a ln (přirozený logaritmus).
- Mocnina a odmocninové funkce: x², x³, √, ³√, xʸ.

Figure 3: Illustration of trigonometric function keys.
3.3 Statistické výpočty
The calculator supports various statistical calculations. To enter STAT mode, press MODE and select the appropriate statistical mode (e.g., SD for standard deviation, REG for regression).
- Vstup dat: Input data points using the M+ klíč.
- Statistical Results: Calculate mean, standard deviation, sum of squares, etc., after data entry.

Figure 4: Illustration of statistical function keys.
3.4 Multi-Replay Function
The Multi-Replay function allows you to recall and edit previously executed formulas. Use the ▲ a ▼ cursor keys to navigate through past calculations. This feature is useful for correcting errors or performing similar calculations with different values.

Figure 5: The Multi-Replay function allows quick recall and editing of previous calculations.
3.5 Constants and Conversions
The calculator includes built-in scientific constants and unit conversion functions. Refer to the detailed function guide for specific constant codes and conversion procedures.
4. Údržba
Správná údržba zajistí dlouhou životnost a optimální výkon vaší kalkulačky.
4.1 Čištění
Wipe the calculator's exterior with a soft, dry cloth. Avoid using abrasive cleaners, solvents, or harsh chemicals, as these can damage the casing and water-resistant key printing.
4.2 Skladování
Store the calculator in a cool, dry place away from direct sunlight and extreme temperatures. Use the provided protective cover to prevent scratches and damage to the keys and display.

Figure 6: Dimensions of the Casio FX-991MS 2nd Gen Calculator (16.2L x 7.7W Centimeters).
5. Řešení problémů
If you encounter issues with your calculator, refer to the following common problems and solutions.
5.1 Problémy se zobrazením
- Prázdný displej: Ensure sufficient light for solar power or that the battery is functional. If the display remains blank, try pressing the ON tlačítko.
- Slabý displej: The battery may be low. While the calculator uses solar power, a weak battery can affect display clarity in certain conditions.
5.2 Incorrect Results
- Režim kontroly: Verify that the calculator is in the correct mode (e.g., COMP for general calculations, STAT for statistics). Press MODE změnit.
- Angle Unit: Ensure the correct angle unit (DEG, RAD, GRA) is selected for trigonometric calculations. Press MODE multiple times to cycle through options.
- Resetovat: If issues persist, perform a full reset. Press POSUN pak CLR (MODE) and select Vše. This will clear all memory and settings.
6. Specifikace
| Funkce | Specifikace |
|---|---|
| Značka | Casio |
| Název modelu | FX-991MS-2 |
| Typ kalkulačky | Engineering/Scientific (Non-Programmable) |
| Počet funkcí | 401 |
| Typ zobrazení | 2řádkový LCD displej |
| Zdroj napájení | Solar & Battery Powered (Nonstandard Battery included) |
| Materiál pouzdra | Plast |
| Rozměry položky (D x Š) | 16.2D x 7.7Š centimetrů |
| Hmotnost položky | 95 gramů |
| Země původu | Thajsko |
7. Záruka a podpora
Your Casio FX-991MS 2nd Gen Scientific Calculator comes with a manufacturer's warranty and dedicated support.
7.1 Záruka výrobce
Na výrobek se vztahuje 3-year All India Manufacturer Warranty from the date of purchase. An additional 6 months warranty can be availed by registering your product online.
- To avail warranty: Produce the original bill copy/invoice at an authorized Casio service center. The warranty card and stamp are not mandatory for online purchases.
- Online registrace: Zaregistrujte svůj produkt na https://register.casio.in for an extended warranty.
7.2 Zákaznická podpora
For any service-related inquiries or feedback, please contact Casio India:
- Číslo linky pomoci: 011-66999200
- E-mail: casiocare@casio.co.in
- Kontaktní údaje výrobce: Casio India Co Pvt Ltd, A-41, 1st Floor, MCIE, Mathura Road, New Delhi-110044