The Minus-Or-Plus Sign symbol (โ). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Math.
The quickest way is to copy โ from this page and paste it anywhere. You can also insert it with its Unicode, HTML, or alt code listed above.
โ is U+2213 (decimal 8723).
Use ∓ in HTML to render โ on a web page.
On Windows you can type it with Alt+8723 (hold Alt and enter the number on the numeric keypad).
Yes โ copying is completely free and unlimited, and works right in your browser with no sign-up.