The numbers from 0 to 20 inclusive are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. Total numbers = 21 Odd prime numbers in this range: Primes must be greater than 1 and have no divisors other than 1 and themselves. Odd primes (exclude 2, which is even): 3, 5, 7, 11, 13, 17, 19 → There are 7 odd prime numbers. 3. Probability = \(\frac{\text{Number of favourable outcomes}}{\text{Total outcomes}}\) = \(\dfrac{7}{21} = \dfrac{1}{3}\)