McDonalds sells Chicken McNuggets in boxes of 6, 9, or 20.
Obviously one could purchase exactly 15 McNuggets by buying a
box of 6 and a box of 9.
Could you purchase exactly 17 McNuggets?
How would you purchase exactly 53 McNuggets?
What is the largest number for which it is impossible to
purchase exactly that number of McNuggets?
What if the McNuggets were available in boxes of 7, 11, and 17?
What is the largest number for which it is impossible to purchase
exactly that number of McNuggests?