SOLUTION

--Static code

set serveroutput on;
DECLARE 
number1 number := 30;
number2 number := 20;
tot number;
sub number;
mul number;
div number;
BEGIN
tot := number1 + number2;
sub := number1 - number2;
mul := number1 * number2;
div := number1 / number2;
dbms_output.put_line('The Addition of 2 number is :-'||tot);
dbms_output.put_line('The subtaction  of 2 number is :-'||sub);
dbms_output.put_line('The multiplication of 2 number is :-'||mul);
dbms_output.put_line('The Division  of 2 number is :-'||div);
END;
/
    



--Dynamic code 
set serveroutput on;
DECLARE 
number1 number := &number1;
number2 number := &number2;
tot number;
sub number;
mul number;
div number;
BEGIN
tot := number1 + number2;
sub := number1 - number2;
mul := number1 * number2;
div := number1 / number2;
dbms_output.put_line('The Addition of 2 number is :-'||tot);
dbms_output.put_line('The subtaction  of 2 number is :-'||sub);
dbms_output.put_line('The multiplication of 2 number is :-'||mul);
dbms_output.put_line('The Division  of 2 number is :-'||div);
END;
/