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Prime numbers to 100

You learn about prime numbers: numbers only divisible by 1 and themselves.

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How to work it out

  1. Try if the number is divisible by 2, 3, 5 or 7.
  2. If none go into it, then it has only two divisors: 1 and itself.
  3. Then it is a prime number.
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Is 7 a prime number?

  1. Can you divide 7 by 2, 3, 4, 5 or 6? No.
  2. Only by 1 and 7.
  3. So 7 is prime.
Another example

Is 12 a prime number?

  1. You can divide 12 by 2, 3, 4 and 6.
  2. So 12 is not prime.