A young boy dropped his deck of baseball cards. Unwilling to count them again he remembered that when he put them in piles of two, there was one card left over. When he put them in stacks of three, there was one card left over. The same thing happened for stacks of 4, 5, 6, but when he put them in stacks of 7, there were no cards left over!
How many cards did the boy have? Is there only one possibility? Can you generalize a solution?
How many cards did the boy have? Is there only one possibility? Can you generalize a solution?