Casio fx-115s - User Manual
This document critiques the design and usability of conventional calculators, advocating instead for a user manual that would redefine how mathematical computations are handled through intuitive, error-resistant interfaces. The text highlights flaws in existing models–such as inconsistent handling of algebra, negative numbers, percentages, and complex operations–and proposes a new approach where calculations are displayed transparently, allowing users to edit expressions dynamically while maintaining accuracy. Key themes include the need for clearer user interaction (e.g., declarative over imperative design), built-in error correction, and standardized problem-solving workflows for advanced math tasks like solving equations or generating number tables.
Table of Contents:
- Page 1 – Critique of Calculators and Introduction to Calculation Methods
- Page 2 – Historical Development and Design Critique
- Page 3 – Limitations in Handling Algebraic Expressions
- Page 4 – Inconsistencies in Calculator Operations
- Page 5 – Limitations of Scientific Calculators
- Page 6 – Common Flaws in Conventional Calculators
- Page 7 – Significance of Calculator Errors
- Page 8 – Design Philosophy of New Calculators
- Page 9 – Specialized Calculation Methods
- Page 10 – Using Logarithmic and Power Functions
- Page 11 – Advanced Functions and Notation Critique
- Page 12 – Concept of a True Calculator
- Page 13 – Handheld Scientific Calculator Design
- Page 14 – Worked Examples in Calculation
- Page 15 – True Calculator Functionalities
- Page 16 – Arithmetic Correction Mechanisms
1
A true calculator
Harold Thimbleby
Swansea University Department of Computer Science
Existing calculators are unreliable and difficult to use, and they are
marketed misleadingly. A new calculator is described that is simple,
reliable and very powerful.
Originally published in
Engineering Science and Education Journal
,
6
(3):128–136, 1997.
This paper provides a selection of worked examples for the n e w
calculator: including working out the radius of a sphere of given weight; a
financial calculation, recreational mathematics (Ramanujan’s 1729
problem), and using the built-in tables of interesting number facts.
C
ALCULATORS
are used in all aspects of work, from laboratories to banks, as
well as in everyday life, from paying loans to passing exams. Handheld
electronic calculators seem impressive, and they have been around long
enough for us to take them for granted. They are ubiquitous: they can be
found in wrist watches or in rulers; they may be credit-card sized, pocket
sized, or ‘desk top’ with their own printer. Calculators are required in school
curriculums, and no office would be complete without one. They are
probably the most commonly used and experienced of all modern
‘information technology’ electronic gadgets.
Calculators are also at the centre of controversy. Our children are not
good at mathematics, and calculators get some of the blame. Is this because
calculators stop children thinking about numbers, so they never learn any
insight into mathematics?
This article suggests that things are worse: the maths that calculators do is
damaged, and learning to use a calculator is really more about learning to
cope with unnecessarily bad technology than about learning about numbers.
The first article on the front page article of
The Times
(December 7, 1995)
entitled, “Calculators banned in exams after maths standards fall,” claimed
that School Curriculum and Assessment Authority officials were worried
about childrens’ falling standards in decimal places, fractions and “lack of
basic understanding of percentage.” Ironically these problems children have
with maths are identical to problems calculators themselves have, as we shall
see. Maybe the problems are not calculators
per se
, but with the way they are
conventionally designed? This article will not only criticise current calculators,
but suggest a workable alternative.
Background
After the abacus, more-or-less unchanged through antiquity, the first main
development in devices for making calculation easier was John Napier’s
invention of logarithms around 1594. (He was also one of the first people to
make systematic use of the decimal point.) Napier later published a book,
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About this manual
- Brand
- Casio
- Model
- fx-115s
- Document type
- User Manual
- Language(s)
- English
- Pages
- 16
- File size
- 482.9 KB
- Format
Summary
An article proposing a superior calculator based on worked examples for sphere radius, finance, recreational math, and historical overview of calculation devices.
Discussion on the evolution of calculators from mechanical devices to modern electronics, critique of current complexity, and proposal for a more user-friendly design.
Critique of conventional handheld calculators regarding their failure to correctly handle algebraic expressions, negative numbers, implicit multiplication, and error handling.
