Suppose you have a list of mobile nos, with a 0 as prefix.
Now you do not want that 0 to be there, and it should be only a 10 digit mobile number.This is simple!
You can use the =RIGHT formula, which extracts the required number of characters, starting from the right part of your data.
Say you have a mobile number with 11 digits (0 as prefix) in cell A1. You want to remove the 0 and have only the remaining 10 digits in cell B1.
Type this formula in B1,
=RIGHT(A1, 10)
This will extract 10 characters starting from right, from cell A1.

Thinking how to extract from the left side, simple, use =LEFT(text, no_of_characters_to_extract)     😉