The next number in the series is always found by dividing the previous number by the number before it. So you calculate the number at position 3 by dividing the number at position 2 by the number at position 1.

140 / 14 = 10

10 / 140 = 1/14

1/14 / 10 = 1/140

1/140 / 1/14 = 1/10

1/10 / 1/140 = 14