Wikipedia:Avoid unicode minus and use numeric keypad minus

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This essay, WP:Avoid unicode minus and use numeric keypad minus, explains search/sort problems when using the Unicode minus-sign (−) and explains template {{msym}} to show a keypad-minus in a font appearing like a unicode minus.

In the Wikipedia Manual of Style, the paragraph "Minus signs" failed to mention the 40-year standard of the minus-key on a numeric keypad, which is what the Wikipedia MediaWiki system uses for negative numbers. The paragraph should have been written to prefer the keypad minus-sign, but to also allow using "−" in some cases:

Minus signs // "Do not use an en dash for negative signs and subtraction operators: the preferred sign is the minus-key on the numeric keypad of a computer keyboard (same as the hyphen), which has been a keyboard standard for over 40 years, and it is also the result generated by Wikipedia, as in subtracting 9 - 10: {{#expr: 9 - 10}} (to yield "-1"). The unicode character for the minus sign (− as "−") could be used for some display purposes. However, the hyphen is preferred when searching a page for negative numbers (matches keypad "-"), or when calculating negative results in a template, or when sorting numbers."

The use of "−" (during 2007-2009) has led to templates generating unusable negative-numbers which will not match a numeric-keypad search, and will NOT sort numerically in sortable tables specified using class="wikitable sortable". However, the WP:MOS standard could be changed in later years, to prefer &minus when the world's keyboards change most numeric keypads, but I don't think that should be stated in the MOS, because of the decades of waiting.

Meanwhile, the template {{msym}} can be used to alter the font and display a keypad-minus (or hyphen) in a font that appears like a unicode minus, such as Courier font. Compare the example of "-3" with {{msym}}3 versus −3:  "-3" with "-3" versus "−3". When searching a page for a hyphen-minus or negative number, then any unicode-minus on the page will fail to match, while any msym-style minus will match.

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