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Use of Non-Standard and Discouraged Arithmetic Operators in Abicus #287

@lumilla

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@lumilla

Abicus currently uses the obelus (÷) and the multiplication cross (×). These are Non-Standard, partially discouraged and disliked by multiple people, including but not limited to myself..

The obelus (÷) is discouraged in the ISO 80000-2 standard for notations used in mathematics, science and technology. More specifically, ISO 80000-2 states that the division sign "should not be used" for division [1]. The standard recommends only the solidus (/) or fraction bar for division, or the colon (:) for ratios [1].

The multiplication cross (×) is problematic for algebraic contexts. In NIST SP 811, the preferred sign for the multiplication of numbers or values of quantities is a cross (×) when the dot is used as the decimal marker[2] (which I'd like to note that it isn't in Finnish notation), however the middle dot (·) is used to represent the multiplication operator[3], particularly for symbols for units formed from other units by multiplication [4].

The concern about the multiplication cross is well-founded: in higher mathematics, the × symbol creates confusion with the variable x and with vector cross products. To reduce confusion between the multiplication sign × and the common mathematical variable x, multiplication is also denoted by dot signs or by juxtaposition [4].

The math editor used in Abitti and thus most Finnish textbooks renders multiplication using \cdot in LaTeX (middle dot notation), creating a visual inconsistency between Abicus and the rest of the Abitti system. This discrepancy may confuse students about proper mathematical conventions.

As a tool used in the Finnish matriculation exams, Abicus should model the precise notation students are expected to use in university and professional scientific writing. These standards are internationally recognized and apply to natural sciences and technology [1].


See:

[1] Wikipedia - Division sign.

[2] NIST Special Publication 811: Guide for the Use of the International System of Units.

[3] Dot Operator Symbol (⋅).

[4] Wikipedia - Multiplication.

I would quote SFS-EN ISO 80000-2:2019, but am unable to afford it as an individual. However, I would expect the Matriculation Examination Board to conform to it.

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