title: "ValueError: Invalid format specifier" when formatting a calculated variable
body: <p>Only my third or so time working with python and since Im following along with a Gaddis textbook, I have to make an ingredient adjuster program for baking cookies. However, the last lines of code where I try and format the numbers, ValueError: Invalid format specifier comes up when I try to run it.</p>
  
  <p>Read some of the questions similar to mine on here, however I found the instances of those programs were much more complicated to understand and relate back to mine.</p>
  
  <pre><code>#The recipe produces 48 cookies with this amount of the ingredients.
  #Write a program that asks the user how many cookies he or she wants to make,
  #then displays the number of cups of each ingredient needed for the specified
  #number of cookies.
  
  #1.5 cups of sugar
  #1 cup of butter
  #2.75 cups of flour
  
  default_batch = 48
  defaultCups_Sugar = 1.5
  defaultCups_Butter = 1
  defaultCups_Flour = 2.75
  
  num_cookies = float(input("How many cookies would you like to make? "))
  
  calCups_Sugar = (num_cookies/default_batch)*defaultCups_Sugar
  calCups_Butter = (num_cookies/default_batch)*defaultCups_Butter
  calCups_Flour = (num_cookies/default_batch)*defaultCups_Flour
  
  print ("It would take the following amount of ingredients to       make", \
     num_cookies, "cookies:")
  
  print ("Cups of Sugar:", format(calCups_Sugar, ";.2f"))
  print ("Cups of Butter:", format(calCups_Butter, ";.2f"))
  print ("Cups of Flour:", format(calCups_Flour, ";.2f"))
  </code></pre>
  
  <p>I expect the output to only go as far as two decimal places however the ValueError: Invalid format specifier error message appears instead when I run it.</p>