Introductory combination problems like if you have 5 friends and can pick 2 of them to join you on a boat ride, how many different groups of friends could you take with you?


Christopher is packing his bags for his vacation. He has 8 unique shirts, but only 5 fit in his bag.
How many different groups of 5 shirts can he take?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, p, i or 2, slash, 3, space, p, i