Question 208548: i cant find the prime numbers to 36 can u help me
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! i cant find the prime numbers to 36 can u help me
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Why not?
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31
The next one is 37, but that's more than 36.
Why were you not able to find those?
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Another approach is to list the numbers 1 - 36, then eliminate all those divisible by 2, then by 3, then by 5, etc.
Just leave out the even numbers, except for 2.
2, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35.
All ending with 5 are divisible by 5, so cross those off (not 5 tho).
2, 3, 5, 7, 9, 11, 13, 17, 19, 21, 23, 27, 29, 31, 33
Then do the 3s, but not 3 itself.
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31
Then 7, but there are none. That's far enough, it's only necessary to test the numbers up to the square root of 36, so it's done.
This is the "Sieve of Erastothsenes", btw. He devised this method over 2000 years ago.
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