What is the Unchecked Keyword in C#?

The unchecked keyword is used to control the overflow-checking context for integral-type arithmetic operations and conversions. It can be used as an operator or a statement according to the following forms.
The unchecked statement:

unchecked block

The unchecked operator:

unchecked (expression)

where:

block

The statement block that contains the expressions to be evaluated in an unchecked context.

expression

The expression to be evaluated in an unchecked context. Notice that the expression must be in parentheses ( ).