On the Subject of The Calculator

For once the bomb makers decided to throw you a bone...

• Take the sum of each character in the serial number, with letters being their alphanumerical position plus nine.
• Input the number onto the calculator and then press solve.
• Other features that The Calculator includes are:
  • Perform any basic arithmetic operation.
  • Square any number and take the square root of any number.
  • Take the digital root of any number.
  • Modulo any number.
  • Assign up to three variables.
• Use the = button to finalize any operation, the C button to clear any input, and the < button to delete the last input.