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# Prime/Perfect/Triangular Numbers & Functions (help) (homework)

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It is called the Sieve of Eratosthenes. The procedure is illustrated below. List all the natural numbers from 1 to Cross out the number 1, because it is not a prime number. The number 2 is prime; circle it. Cross out all the other multiples of 2 4, 6, 8,… because they are not prime. The number 3 is prime; circle it. Cross out all the other multiples of 3 6, 9, 12,… that are not already crossed out.

The number 4, the next consecutive number in the list, has already been crossed out. The number 5 is prime; circle it. Cross out all the other multiples of 5 that are not already crossed out. Continue in this manner until all the prime numbers less than are circled. Then scan each number to see what numbers add up to it. Eight is 5 and 3, 10 is 7 and 3, 12 is 5 and seven, 14 is eleven and 3, sixteen is 13 and three, 18 is 11 and seven, and 20 is thirteen and 7.

Too tired to continue lovemaths. Related Questions Maths Homework Help. First year maths homework help prime numbers? Maths homework factors and prime numbers?? Math homework help with prime numbers? Answer Questions Which are the best websites for homework help? Requests for help with cheating, plagiarism, or other violations of academic integrity; violations of copyright or terms of use; or other illegal or unethical activities.

Keep in mind that we do not and will not have any sort of vetting procedure for responders. Accept answers at your own risk. We use automoderator for a few things. It may delete a post erroneously. We ban all bots. Natural numbers that are greater than one that are not prime are composite Note that 1 is neither prime nor composite. I have no clue how to approach this problem. How do I test every number? How about proof by contradiction? This is a contradiction Use of this site constitutes acceptance of our User Agreement and Privacy Policy.

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The definition of a prime number is any number greater than one that can only be divided evenly by 1 and itself.. Therefore, 2 is a prime number because its only factors are 1 and 2, and 3 is a prime number because its only factors are 1 and 3. .

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Finding Prime Factors If every number (over 1) can be expressed as an unique product of prime numbers, what does that mean? For one thing, it means that one can factor numbers completely to find prime factors. Looking at the number 24, it can be factored as 3 X 8. Three is a prime number, but 8 is not. Eight is the product of 2 X 2 X 2.