Select all prime numbers from the list: 21, 29, 31, 49.
Note
29 and 31 are prime because they have no positive divisors other than 1 and themselves; 21 and 49 are composite (21 = 3×7, 49 = 7×7).
Select all prime numbers from the list: 21, 29, 31, 49.
29 and 31 are prime because they have no positive divisors other than 1 and themselves; 21 and 49 are composite (21 = 3×7, 49 = 7×7).