Question

SH
Exercise 18
1. Which of the following numbers are prime numbers?
1,11,21,57,67,19,91,63,83,89
2. Which of the following numbers are composite numbers?
1, 79, 97, 51, 61, 87, 81, 78, 93, 47
3. List all prime numbers between 1 and 50.
4. List all prime numbers between 51 and 100.
5. List all twin-primes between 1 and 50.
6. List seven consecutive composite numbers less than 100.
7. Give four examples of pairs of co-primes ​

Answer 1

Answer:

2 ,4 ,6,8,10,12,14,16,18,20