Shell shift procedure - What is this?

Question

In shell we have the command shift, but i saw on some example its giving shift 3

Why there is a number after shift ? and what its about ? what it does ?

Example:

Answer 1

Shift the positional parameters to the left by n. The positional parameters from n+1 ... $# are renamed to $1 ... $#-n. Parameters represented by the numbers $# to $#-n+1 are unset. n must be a non-negative number less than or equal to $#. If n is zero or greater than $#, the positional parameters are not changed. If n is not supplied, it is assumed to be 1. The return status is zero unless n is greater than $# or less than zero, non-zero otherwise.

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