- 23 - 16 -34 Let A = 504 320 670 Find the second and third columns of A 1 without computing the first column. 142 85 184 How can the second and third columns ofA be found without computing the first column?

1 is the only number that has just one positive divisor and we call it a unit. 1 divides every number. 3 is a number that has exactly two positive divisors. Its divisors are 1 and 3. A number with exactly two divisors is called a prime. 12 is a number with six divisors. Its divisors are 1,2,3,4,6,12. A number with more than two positive divisors is called composite. The smallest number that is a prime is The smallest number that is composite is There are primes that are less than 10. There are composites that are less than 10. The smallest prime greater than 50 is