Euclid was a Greek mathematician, and is called the father of geometry.
A Prime number is any number that can only be divided by itself and one. There are an infinite number of prime numbers. As a mathematician Euclid was interested the pursuit of knowledge for knowledge's sake and in proving that things could be quantified (how many, how much). In the case of primes the answer of "there are an infinitely large number of primes" was not available to him as the Greeks did not have the concept of "infinite".
Euclid (c. 300 BC) was one of the first to prove that there are infinitely many prime numbers. His proof was essentially to assume that there were a finite number of prime numbers, and arrive at a contradiction. Thus, there must be infinitely many prime numbers. Specifically, he supposed that if there were a finite number of prime numbers, then if one were to multiply all those prime numbers together and add 1, it would result in a number that was not divisible by any of the (finite number of) prime numbers, thus would itself be a prime number larger than the largest prime number in the assumed list - a contradiction.
I suggest factoring each pair of numbers, and checking whether they have, or don't have, common factors. A pair of numbers is said to be "relatively prime" if they have no common factors (their greatest common factor is 1). For larger numbers, Euclid's algorithm could be used, but for such small numbers, factoring is probably faster.
There is infinite amount of prime numbers. The largest known prime number is 243,112,609 − 1. It is a number with thirteen million digits. Greek mathematician Euclid proved it with the fact that if you multiply any given set of prime numbers and ad 1 you get either a prime number, or one that has smaller prime numbers - none of which is part of the original set. Example set: 2, 3, 5 2*3*5=30 30+1=31 Because of the added one, 31 is not divisible by 2, by 3, or by 5. (In this case, it happens to be a prime number.) For more info and more proofs that there is infinite number of prime numbers, check related link.
This can be an extension to the proof that there are infinitely many prime numbers. If there are infinitely many prime numbers, then there are also infinitely many PRODUCTS of prime numbers. Those numbers that are the product of 2 or more prime numbers are not prime numbers.
The set of prime factors of the numbers from 1 to 15,000 would be the set of prime numbers between 1 and 15,000. The link below has a list of the first 10,000 prime numbers, so if you take the primes less than 15,000, you will have the set of prime factors of the first 15,000 numbers. For prime factors of individual numbers, check the related question, "What are the prime factors of the numbers from 1 to 200?" Also check for WikiAnswers questions in the form of "What are the prime factors of __?" and "What are the factors and prime factors of __?"
Was demonstrated by Euclid around 300 B.C
No one invented prime numbers.
Euclid
The Egyptians were the first people to have some knowledge in prime numbers. Though, the earliest known record are Euclid's Elements, which contain the important theorem of prime numbers. The Ancient Greeks, including Euclid, were the first people to find prime numbers. Euclid constructed the Mersenne prime to work out the infinite number of primes.
Euclid
Euclid proved that it is impossible to find the "largest prime number," because if you take the largest known prime number, add 1 to the product of all the primes up to and including it, you will get another prime number. Euclid's proof for this theorem is generally accepted as one of the "classic" proofs because of its conciseness and clarity. Millions of prime numbers are known to exist, and more are being added by mathematicians and computer scientists. Mathematicians since Euclid have attempted without success to find a pattern to the sequence of prime numbers.
Euclid
No, prime numbers already existed. Euclid simply made some important mathematical contributions related to prime numbers. Among others, he discovered a surprisingly simple proof that the set of prime numbers is infinite; and he discovered that the prime factorization of any natural number is unique.
Euclid contributed to number theory, which is the study of integers. He worked on prime numbers and divisibility. He proved the infinitude of prime numbers, which had not been proven before.
You can use Euclid's algorithm to calculate the gcf of two of the numbers - then use Euclid's algorithm again with the result and the third number.Or you can factor all the numbers into prime factors, and check which prime factors occur in all three numbers.
Euclid's algorithm is probably the most commonly used 'formula' for that purpose. If the greatest common factor is 1, the numbers are relatively prime. See the related question for an example of Euclid's algorithm.
Euclid (c. 300 BC) was one of the first to prove that there are infinitely many prime numbers. His proof was essentially to assume that there were a finite number of prime numbers, and arrive at a contradiction. Thus, there must be infinitely many prime numbers. Specifically, he supposed that if there were a finite number of prime numbers, then if one were to multiply all those prime numbers together and add 1, it would result in a number that was not divisible by any of the (finite number of) prime numbers, thus would itself be a prime number larger than the largest prime number in the assumed list - a contradiction.