The **Casio Deluxe Memory** is an early calculator released by Casio Computer Company in 1974. This calculator has a horizontal format two-piece case made of smooth black and white plastic. The display is recessed and tilted, showing 8 blue vacuum fluorescent digits. It can display up to 16 digits of precision using a shift key. The Casio Deluxe Memory measures approximately 156mm x 82mm x 30mm and weighs 186g without batteries.

This calculator requires 6V DC power, supplied by 4 AA batteries or an AC adapter. It has full-sized, hollow-sounding plastic keys that give a satisfying tactile feedback when pressed. The key area is outlined by a deep groove that unfortunately tends to collect dirt. A slightly inset neutral display filter allows for a bright, crisp display.

For a calculator of its time, the Casio Deluxe Memory has impressive capabilities. It is a 4 function calculator that can handle addition, subtraction, multiplication and division. It also has a total key for summation, percentages, and a display shift key for increased precision. The total key allows incremental summation as well as decrementing.

Some other notable features:

- 8 digit vacuum fluorescent display
- Blue display color
- Horizontal format case
- Full-sized plastic keys
- Tilted recessed display
- Display shift for increased precision
- Total summation and decrement
- Percentage calculation
- Powered by batteries or AC adapter

Logic:

- Clears last number entered with C key
- Clears entire calculator with AC key
- Overflow suppressed on number input
- Overflow error not recoverable
- Divide by zero error allowed
- Automatic constant on multiply and divide only
- Memory system requires manual tracking
- Negative indicated by “-” in leftmost digit
- Negative zero and divide by zero bugs

While the Casio Deluxe Memory has some logic quirks, it represents an early full-featured calculator in Casio’s line. It provides the core functionality needed for most calculations along with helpful extras like the total key. The build quality is solid despite the loose internal construction. For 1974, this calculator gave good value and brought increased math power to the average consumer.