There are special chatracters you may want to type like a ¢ (cent) sign or £ (pound) sign or ± (plus/minus) sign. The way to do it is to hold the ALT key and use the numbers on the right side of the keyboard ( numbers on the first row of the keybaord wont work). Once you type the 3-difgit or 4-digit number, release the ALT key and you get the character.

Here are a few examples

ALT + 0199 = Ç
ALT + 0177 = ±
ALT + 0699 = »
ALT + 133 = à
ALT + 277 = §

There are many characters like arrows etc.
I hope if someone can find the whole list to provide a link
It is very useful sometimes.