Two numbers are chosen from 1-5 the probability that the two numbers are consecutive is

The consecutive numbers can be (1,2) (2,3) (3,4) (4,5). Usually consecutive things are n-1. Like you had to select consecutive numbers out of 5 numbers. So cases of consecutive numbers are 5-1 = 4
Now no, of ways of selecting 2 numbers out of 5 = ⁵C₂ = 10.
So probability = 4/10 or 2/5