Don't know how to do it ?
It's simple....
Just hold down the Alt key and on the keypad type 248 then let off on the Alt key.....
Like this : ? , you see there it is.....
Example .... 248?F or 248?C ....
Try other numbers, like ... 249 = ∙ 251 = √ , 242 = ⁿ, etc...
≡?≥≤⌠⌡?≈?∙?√ⁿ?■
Have Fun !