Pocket calculator Centrum model 80406, compact 105×57×12 mm, solar with button battery backup

Compact pocket calculator Centrum model 80406 measures approximately 105×57×12 mm and combines a solar cell with a button battery backup to ensure continuous operation in varying light conditions. It provides essential arithmetic functions in a small, lightweight housing designed for carrying in a pocket, pencil case or bag. The device is intended for basic calculations such as addition, subtraction, multiplication and division, and supports everyday numerical tasks for students, office workers and retail staff.

Advantages

This pocket calculator delivers a compact footprint and low weight while maintaining clear, easy-to-read keys and display. The dual power source—solar panel supplemented by a button cell—offers extended runtime and reliable performance indoors and outdoors. Its simple layout reduces learning time and enables fast, accurate entry for routine calculations. The sturdy plastic casing resists minor impacts and fits easily into small storage spaces.

Suitable for

• Basic schoolwork and homework calculations
• Everyday office arithmetic, expense and invoice checks
• Retail point-of-sale quick calculations and pricing checks
• Travel and field use where portability is required
• Home budgeting and simple financial totals

Key specifications

• Approximate dimensions: 105 × 57 × 12 mm
• Power supply: solar cell with button battery backup
• Function set: basic arithmetic (addition, subtraction, multiplication, division)
• Display: compact numeric display suitable for simple calculations
• Housing: lightweight plastic casing designed for portability

How to use

Place the calculator where the solar cell receives ambient light for primary power; the button battery provides backup when light is insufficient. Turn on the device by pressing any numeric key if required, then enter numbers and operations using the keypad. Use the clear or reset key to correct entries and the equals key to obtain results. Store the calculator in a pocket, pencil case or bag when not in use to keep it protected from scratches and debris.

Usage recommendations

For reliable performance, avoid prolonged exposure to direct sunlight that could heat the unit excessively and replace the button battery if the display dims under normal indoor lighting. Clean the keypad and display gently with a soft, dry cloth and avoid liquid exposure. For consistent daily use, keep the calculator in locations where ambient light regularly reaches the solar cell.