What is the method for verifying if a number is prime?

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There are different methods to verify if a number is prime, but one common method is the trial division method:

1. Start with the number n that you want to test for primality.
2. Find the square root of n and round it up to the nearest integer. Call this number m.
3. Check if n is divisible by 2 or 3. If it is, then n is not prime.
4. Start with i=5 and check if n is divisible by i or i+2. Continue this process up to m. If none of the numbers in this interval divide n, then n is prime.

For example, to test if 23 is prime:

1. Start with n=23.
2. The square root of 23 is about 4.8, so m=5.
3. 23 is not divisible by 2 or 3.
4. Check if 23 is divisible by 5 or 7. Since neither 5 nor 7 divide 23, we can conclude that 23 is prime.