To determine if 1998 is a prime number or a composite number, we simply look at the factors for 1998.
If the factors of 1998 are only 1998 and 1, then we know that 1998 is a prime number. Otherwise, 1998 is a composite number.
To explain better, if 1998 is only divisible by 1 and 1998, then it is a prime number, and if 1998 is divisible by more than 1998 and 1, then it is a composite number.
The factors of 1998 are as follows:
1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999, 1998
Therefore, since 1998 is divisible by more than one and itself, the answer to the
question "Is 1998 prime or composite?" is highlighted in blue below.
composite
Is 1999 prime or composite?
OK. Now you know that 1998 is a composite number. Use our logic above and see if
you can figure out if the next number on our list is prime or composite before you check your answer.
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