The difference between the reciprocal of two natural numbers is 1 in 12. How many of these two numbers are

The difference between the reciprocal of two natural numbers is 1 in 12. How many of these two numbers are

Let two natural numbers be x and y, then 1 / X-1 / y = 1 / 12, that is, (X-Y) / xy = 1 / 12
∵ x, y are natural numbers ∵ xy = 12, Y-X = 1 ∵ x = 3, y = 4