Hi there!
23 is a prime number because it has only two factors - 1 and itself.
Remember, a factor is a number that a number can be evenly divided by. So 3 is not a factor of 23.
11 is prime as well.
25 is a composite number because it's last digit is 5. If a number's last digit is 5, then it's divisible by 5. Therefore, it's composite.
19 is a prime number.
Hope you find this helpful!
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