Find probability of prime number between 1to10 natural numbers

the first 10 natural numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
no. of prime numbers = 4 (2, 3, 5, 7)

P (prime no.s between 1 to 10) = 4/10 = 2/5