Prime and Composite Numbers
Prime NumbersA Prime Number can be divided evenly only by 1 or itself. And it must be a whole number greater than 1.
For example: 5 is prime, as only 1 and 5 divide it, whereas 6 is composite, since it has the divisors 2 and 3 in addition to 1 and 6. Factors of 1 and the number itself makes the number prime. 2: 1 x 2 only even prime number 3: 1 x 3 5: 1 x 5 7: 1 x 7 Prime Numbers RAP 
Optimus  Prime Number.

Composite NumbersA Composite Number can be divided evenly
by numbers other than 1 or itself. For example: 4 is composite, since it has divisors of 2 and 2 in addition to 1 and 4. Having more than 2 factors (1 & itself) makes the number a composite number. 4: 1, 2, and 4 6: 1, 2, 3, and 6 8: 1, 2, 4, and 8 9: 1, 3, and 9 
Eratosthenes  Greek Mathematician Born: 276 BC in Cyrene, North Africa (now Shahhat, Libya)
Died: 194 BC in Alexandria, Egypt
A prime number is a number that can be divided evenly only by 1 and itself. “Divided evenly” means that the result is a whole number, with no remainder. Prime numbers and their properties were first studied extensively by ancient Greek mathematicians, including Eratosthenes (pronounced AIRaTOSStheknees).
Sieve of EratosthenesIn mathematics, the Sieve of Eratosthenes is a simple, ancient algorithm for finding all prime numbers up to a specified integer. It works efficiently for the smaller primes (below 10 million). It was created by Eratosthenes, an ancient Greek mathematician.
Sieve of Eratosthenes
Eratosthenes Sieve  can change size of gridEratosthenes SieveSieve explainedThe Prime Counter  Murderous Math 
Prime & Composite Numbers
Sieve of Eratosthenes  acoe.orgSlide Show  excellent
Sieve  column of 6The PRIME TesterPrime or Composite Number?Math Pickle
Sieve–noun
1.
an instrument with a meshed or perforated bottom, used for separating coarse from fine parts of loose matter, for straining liquids, etc., esp. one with a circular frame and fine meshes or perforations.
2.
a person who cannot keep a secret.
Sieve Harcourt eLab

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