Consider the numbers 13, 16, 27, and 41.
a. Which of these numbers are prime? How do you know?
b. Which of these numbers are composite? How do you know?
a. The numbers 13 and 41 are prime because they only have two factors, 1 and themselves.
b. The numbers 16 and 27 are composite because they have more than two factors. For example, 16 can be divided evenly by 1, 2, 4, 8, and 16. Similarly, 27 can be divided evenly by 1, 3, 9, and 27.