question_answer 1)

Write down separately the prime and composite numbers less than 20.

Answer:

                Prime numbers are those numbers whose only factors are 1 and the number itself. So, prime numbers less than 20 are 2, 3, 5, 7, 11, 13, 17 and 19. Composite numbers are those numbers which have more than two factors. So, composite numbers less than 20 are 4, 6, 8, 9, 10, 12, 14, 15, 16 and 18.