example:

±

the html code for plusmn is

±
this is the information you will need to create the HTML character for plus on top of minus sign:

Code Name: plusmn
Character: ±
Unicode Code Point (Decimal): U+00B1 (177)
Standard: HTML 3.2
DTD: HTMLlat1
Old ISO Subnet: ISOnum
Description: plus-minus sign (= plus-or-minus sign)

what else besides plus-minus sign (= plus-or-minus sign) do you want to know the html code?