Dash as multiplication sign in older texts

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    Multiplication Sign
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Discussion Overview

The discussion revolves around the use of a dash (-) as a multiplication sign in older texts, particularly in the context of units of measurement. Participants explore its origins and implications for clarity in scientific communication.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants note the use of a dash as a multiplication sign, particularly in relation to units, and question its origin.
  • One participant suggests that the dash functions as a hyphen, amalgamating two words into a single hyphenated term.
  • Another participant expresses confusion over units formatted as "mg m-3-years," indicating that such notation can lead to ambiguity in interpretation.
  • A later reply discusses the challenges of typing units clearly, proposing that the hyphen can help ensure clarity in the representation of units over alternatives like slashes.
  • Additionally, a suggestion is made to create new units to avoid confusion, such as equating Newton-metres to joules.

Areas of Agreement / Disagreement

Participants express differing views on the clarity and utility of using a dash as a multiplication sign, with some finding it helpful while others find it confusing. The discussion remains unresolved regarding the best practices for unit representation.

Contextual Notes

Participants highlight limitations in clarity and interpretation when using dashes in unit notation, but do not resolve the underlying issues or assumptions about their use.

DrDu
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Sometimes I have seen a dash (-) being used as multiplication sign, usually in connection with units. Does anybody know where this strange custom has it's origin?
 
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DrDu said:
Sometimes I have seen a dash (-) being used as multiplication sign, usually in connection with units. Does anybody know where this strange custom has it's origin?
It's a hyphen: it's taking the two words and amalgamating them into a single hyphenated word.
 
Nevertheless I find units like "mg m-3-years" very confusing.
 
There is sense in that statement.

Consider some poor Physics Forum member typing here

mg / m3 years

or

mg / m3 /years

or

(mg / m3) years

you try typing this and then have a doubt as to whether the years should be on the top or the bottom. Or whether others will interpret it as you have.

The hyphen is a good way to make certain.

Another way is simply to coin a new unit.

eg

Newton-metres = joules

go well
 

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