math symbolsUse real symbols, not alphabetic characters
If you need math symbols infrequently—some light addition and subtraction, the occasional negative number—you can get by without special symbols. Use the plus sign (+) and equals sign (=) as usual. Use the en dash as a minus sign (–) (see hyphens and dashes).
If you need to do multiplication or beyond, insert real math symbols by hand.
|123 x 345 - 678 = 41757||wrong|
|123 × 345 − 678 = 41757||right|
How to insert math symbols
Word Insert → Symbols panel → Symbol → More Symbols
OS X Word 2011 Insert → Symbol → Advanced Symbol
OS X Word 2016 Insert menu → Advanced Symbol
Pages Edit → Emoji & Symbols (or control + ⌘ + space). In the resulting character palette, if you don’t see a list of symbol categories on the left, change the view by scrolling to the top of the palette and clicking the button in the upper right. From the list on the left, select Math Symbols. Double-click the symbol you want. (Special handling is needed for foot and inch marks.)
HTML Minus sign is
− multiplication sign is
× division sign is
÷ (many others are also supported)