Maximum PC

CL-USER>
(defun number-game (num-guesses)
  (let ((num (+ (random 90) 10)))
    (dotimes (i num-guesses)
      (format t "~%You have ~a chances left to guess the number.~%" (- num-guesses i))
      (format t "Guess? ")
      (setq guess (read))
      (cond ((< guess num)
        (format t "You guessed too low!~%"))
       ((> guess num)
        (format t "You guessed too high!~%"))
       (t
        (format t "You guessed correctly!~%")
        (return t))))))
NUMBER-GAME
CL-USER> (number-game 7)

You have 7 chances left to guess the number.
Guess? 50
You guessed too low!

You have 6 chances left to guess the number.
Guess? 75
You guessed too high!

You have 5 chances left to guess the number.
Guess? 67
You guessed too low!

You have 4 chances left to guess the number.
Guess? 71
You guessed too low!

You have 3 chances left to guess the number.
Guess? 73
You guessed too low!

You have 2 chances left to guess the number.
Guess? 74
You guessed correctly!
T
CL-USER>