Feedback on free time calculator


I started coding about a week ago and want feedback on a free time calculator project. I’m not trying to create anything fancy that I’ll actually use; rather, I’m trying to learn to write code effectively.

I’m looking for feedback on the way I organized my code. Is there a more effective way to have written this code? Thanks!

#this program will calulate the user's free time. 
#The user will be able to chose whether it also 
#calculates free time percentage based on waking time.

print "The program is operating."

def sleep(time):
  sleep_hours = float(raw_input("How many hours do you sleep a night?: "))
  return time - sleep_hours

def work(time):
  work_hours = float(raw_input("How many hours do you work each weekday?: "))
  time -= work_hours
  return time

def see_percent():
  reply = raw_input("Would you like to know the percent of your waking time is free time? (Y/N): ").lower()
  if reply == "y":
    print percent_round + "%."
  elif reply == "n":
    print "Okay"
    print "Y/N means enter a 'Y' for yes or a 'N' for no."

time = 24.
time_minus_sleep = sleep(time)
time_minus_work = work(time_minus_sleep)
waking_time = time_minus_sleep
percent_free = str(time_minus_work / waking_time * 100)
percent_round = percent_free[:5]

print "You have %.2f hours of freetime." % time_minus_work
waking_time = time_minus_sleep
print "Of the %.0f hours in a day, you are awake for %.2f of them." % (time, waking_time)