Contribute correction: Optellen en Aftrekken tot 100

  _____     _____    _    _     _____   
 / ____||  |  ___|| | |  | ||  |  ___|| 
/ //---`'  | ||__   | |/\| ||  | ||__   
\ \\___    | ||__   |  /\  ||  | ||__   
 \_____||  |_____|| |_// \_||  |_____|| 
  `----`   `-----`  `-`   `-`  `-----`