CASE statement in Calculated column

Hi Frzz,

I have below requirement in Calculated column with CASE statement. Could some one help me how to achieve this with case statement.

String  =   0Hello

                01Hello

                012Hello

                0123Hello

If  1st Character of the string is '0' then  -  0Hello

    1st 2 characters of the String is '01'  -   22Hello

    1st 3 characters of the String is '01'  -   333Hello

    1st 4 characters of the String is '01'  -  4444Hello

Thank you.

Best Regards,

Krishna.