Prime and Composite Numbers
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Sieve of Eratosthenes. Follow these steps: Step 1: Starting from the first number select the numbers divisible by 2 and choose "div by 2" in the drop box. Step 2: Among the remaining numbers select the numbers divisible by 3 and choose "div by 3" in the drop box. Step 3: Continue for numbers divisible by 5 and 7. Remember to work only on the remaining unselected numbers each time. Step 4: The numbers that finally remain unselected (left behind) are the prime numbers of the group. |
Write them in order, in the text boxes below.
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15 |
16
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17 |
18 |
19 |
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20 |
21 |
22 |
23 |
24 |
The prime numbers between 15 and 25 ⇒ , and
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