A little girl counts using the fingers of her left hand as follows: She starts by calling her thumb 1, the pointer finger 2, middle finger 3, ring finger 4, and pinky finger 5.

Then she reverses direction (on the same left hand), calling the ring finger 6, middle finger 7, pointer finger 8, and thumb 9, after which she calls her pointer finger 10 and so on.

If she continues to count in this manner, on which finger will she stop?

What if the girl counts from 1 to 10
What if the girl counts from 1 to 100
What if the girl counts from 1 to 1000