wich is not a prime number 11 21 31 41
Right!
Which of those numbers can be divided evenly by numbers other than 1 and the number itself?
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21
To determine which number is not a prime number among 11, 21, 31, and 41, we need to check if each number is divisible by any number other than 1 and itself.
Starting with 11, we check if it is divisible by any number between 2 and 10. We find that 11 is not divisible by any of these numbers, so it passes the test.
Next, we check 21. This number is divisible by 3, so it is not a prime number.
Continuing to 31, we determine if it is divisible by any number between 2 and 30. Since no such number is a divisor of 31, it is a prime number.
Finally, we examine 41. Similar to 31, 41 is not divisible by any number between 2 and 40, so it is a prime number.
Therefore, among the given options, the number that is not a prime number is 21.