How to judge whether a number is prime or composite?

A prime number is a number that can only be divisible by 1 and itself
2,3,5,7,11,13,17,19,23,29,31
A composite number is a number other than prime and one
4,6,8,9,10,12,14,15,16,

RELATED INFORMATIONS

1. If a prime product and a composite product are 36 and 15, then the prime number is () and the composite number is ()
2. 1) - x ^ 4 + x ^ 2 y ^ 2) 3 [(a + b) ^ 2-9c ^ 2] 3) 16 (x + y) ^ 2-25 (X-Y) ^ 2 factorization
3. Factorization (1) 16-24 (a + b) + 9 (a + b) ^ 2 (2) (X-Y) ^ 2-4 (x-y-1) (3) m (X-Y) ^ 2-x + y (4) 9 (a-b) ^ 2-16 (a + b) ^ 2
4. Factorization (x + y) ^ 2 + (x + y) - 20
5. Factorization of 4 (x + y) 2 + 25-20 (x + y)
6. Using factorization to calculate the square of 34 + 34 * 32 + 16
7. If a, B, C and D are four collinear points, then the number of non-zero vectors obtained by taking them as the starting point and the ending point of the vector is zero_____ Ask you mathematical genius to help, to process, logical reasoning is OK, thank you
8. For a 200 meter long runway, each runway is 1.2 meters wide. How many meters should the starting point of the outer lane be moved forward?
9. The following is the schematic diagram of 200m runway, with its end point and starting point on the straight track. As the middle of the runway bypasses the semicircle, the starting point of the outer runway should be moved forward. If each runway is 1.2m wide, how many meters should the starting point of the outer runway be moved forward? (accurate to 0.1M)
10. Finding (2a + axb-3b) x (- a) with the module of vector a * b = 2. A as 1
11. Is 269 a prime number or a composite number? What is the calculation idea? We already know that it's a prime number. We need to calculate the main idea
12. How to judge whether 269 is prime or composite
13. Are 269 and 493 combined or prime numbers
14. Judgment: the product of prime number and prime number must be composite number ()
15. Is 497111121111 prime or composite?
16. On what basis are composite numbers and prime numbers judged
17. How to judge whether 197 is prime or composite
18. How to quickly judge whether it is prime or composite?
19. What are the definitions of prime number and composite number?
20. What is the concept of prime number? Is 2 a prime number? Is prime number a composite number? Please answer these three questions in turn