Question 1
Which of these is a prime number? 21 / 39 / 37 / 49
Tell a prime number from a composite number
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Question 2
Which of these is a prime number? 83 / 63 / 87 / 49
Question 3
Which of these is a prime number? 99 / 19 / 33 / 77
Topic quiz
Five questions on this topic, marked at the end. No hints and no answers along the way — that is what makes the result mean something.
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