How many odd five-digit counting numbers can be formed by choosing digits from the set {1, 2, 3, 4, 5, 6, 7, 8} if digits can be repeated?
+2666 8 options for the first, 8 for the second, 8 for the third, 8 for the fourth, and 4 for the fifth because it has to be odd.
So, there are 8 x 8 x 8 x 8 x 4 options.
