1. Introduction
Thank you for choosing the OSALO OS-5M Desktop Calculator. This manual provides essential information for the proper setup, operation, and maintenance of your calculator. Designed for ease of use with a large display and big buttons, this 12-digit calculator is suitable for various daily tasks in office, school, or home environments.

Image: The OSALO OS-5M desktop calculator positioned on a white desk, alongside a coffee cup and various documents, illustrating a typical usage scenario.
2. Product Overview
The OSALO OS-5M calculator features a user-friendly design with clear components for efficient operation.
Key Features:
- Large Angled Display: A 4.5-inch LCD screen, ergonomically angled for improved readability from various viewing positions.
- Big, Soft Keys: Keys are generously sized and designed for a soft touch, ensuring precise and comfortable input.
- Visualized Operator Symbols: Displays icons for addition, subtraction, multiplication, and division on the screen, providing clear visibility of calculation steps.
- Dual Power Source: Operates primarily on solar energy. For low-light conditions, it can be powered by one AAA battery.
- Durable Construction: Made from high-strength ABS plastic, offering lightweight portability and resistance to impacts.
- Automatic Shutdown: The calculator automatically powers off after 8 minutes of inactivity to conserve energy.

Image: A detailed view of the OSALO OS-5M calculator highlighting its clear LCD screen, the soft, ergonomically shaped keys, and the tactile '5' key designed for easy finger placement.
3. Setup
3.1 Battery Installation
- Locate the battery compartment on the back of the calculator.
- Slide the battery cover open.
- Insert one AAA battery, ensuring the polarity (+/-) matches the diagram inside the compartment.
- Close the battery cover securely.
The calculator is designed for dual power. It will primarily use solar power when sufficient light is available. The AAA battery provides power in low-light conditions or when solar power is insufficient.

Image: A comparison showing the front and back of the OSALO OS-5M calculator. The back view clearly indicates the location of the battery compartment.
4. Operating Instructions
Familiarize yourself with the calculator's key functions for efficient use.
4.1 Basic Arithmetic Operations
- Addition (+): Enter the first number, press +, enter the second number, then press =.
- Subtraction (-): Enter the first number, press -, enter the second number, then press =.
- Multiplication (×): Enter the first number, press ×, enter the second number, then press =.
- Division (÷): Enter the first number, press ÷, enter the second number, then press =.
4.2 Clear Functions
- AC (All Clear): Clears all entries and calculations, including memory.
- C/CE (Clear Entry/Clear): Press once to clear the last entered number. Press twice to clear the current calculation.
4.3 Memory Functions
- M+ (Memory Plus): Adds the displayed value to the memory.
- M- (Memory Minus): Subtracts the displayed value from the memory.
- MRC (Memory Recall/Clear): Press once to recall the memory value. Press twice to clear the memory.
4.4 Other Functions
- % (Percentage): Used for percentage calculations. For example, to calculate 10% of 200, enter 200 × 10 %.
- GT (Grand Total): Accumulates the results of multiple calculations. Press GT to display the grand total.
- √ (Square Root): Calculates the square root of the displayed number.

Image: A clear view of the OSALO OS-5M calculator, emphasizing its large, easy-to-press buttons and the 12-digit display which shows arithmetic symbols during calculations for enhanced clarity.
5. Maintenance
5.1 Cleaning
To maintain the calculator's appearance and functionality, wipe the surface with a soft, dry cloth. For stubborn dirt, slightly dampen the cloth with water. Avoid using harsh chemicals, abrasive cleaners, or solvents, as these can damage the plastic and display.
5.2 Battery Replacement
If the display becomes dim or the calculator functions erratically in sufficient light, the AAA battery may need replacement. Follow the battery installation steps in Section 3.1.
5.3 Storage
Store the calculator in a cool, dry place away from direct sunlight and extreme temperatures. Prolonged exposure to heat or cold can affect battery life and display performance.
6. Troubleshooting
- Calculator does not turn on: Ensure there is sufficient light for solar power or check if the AAA battery is correctly installed and not depleted. Replace the battery if necessary.
- Incorrect calculation results: Press the AC key to clear all previous entries and memory, then re-enter your calculation.
- Display is dim or blank: Move the calculator to a brighter area for solar charging, or replace the AAA battery.
- Keys are unresponsive: Ensure no debris is lodged under the keys. Gently press the keys to ensure proper contact.
7. Specifications
| Feature | Detail |
|---|---|
| Model Number | OS-5M |
| Display Digits | 12 Digits |
| Display Type | LCD |
| Screen Size | 4.5 Inches |
| Power Source | Solar Power, 1 x AAA Battery |
| Material | High-strength ABS Plastic |
| Product Dimensions | 19L x 14.8W cm |
| Weight | 170 Grams |
| Calculator Type | Business/Basic |

Image: A visual comparison of the OSALO 5M and OSALO 6M calculators, detailing their respective dimensions in both inches and millimeters to illustrate size differences.
8. Warranty and Support
For warranty information or technical support, please refer to the product packaging or contact OSALO customer service through the retailer where the product was purchased. Keep your purchase receipt for warranty claims.





