Select all the prime numbers from the list: 31, 39, 41, 49. Select all the ones that are prime.
Note
31 and 41 are prime because they have only divisors 1 and themselves; 39 and 49 are dense numbers (39 = 3×13, 49 = 7×7).
Select all the prime numbers from the list: 31, 39, 41, 49. Select all the ones that are prime.
31 and 41 are prime because they have only divisors 1 and themselves; 39 and 49 are dense numbers (39 = 3×13, 49 = 7×7).