Choose all of the following numbers that are prime: 15, 17, 19, 21.
Note
17 and 19 are prime because they have no divisors other than 1 and themselves; 15 and 21 are composite (15 = 3×5, 21 = 3×7).
Choose all of the following numbers that are prime: 15, 17, 19, 21.
17 and 19 are prime because they have no divisors other than 1 and themselves; 15 and 21 are composite (15 = 3×5, 21 = 3×7).