smith numbers

Prime numbers have been a popular topic in the news.  Below is a strip about working with composite and prime numbers, using what are called Smith Numbers.  Smith Numbers are composite, but identified when the sum of the individual digits in the number are equal to the sum of the prime factors!

Now let’s take a look at 27.  The number 27 is probably most easily identified by school children as being 9 • 3. However, 9 is composite, so instead let’s take the 9 and look at it as 3 • 3.  Now we have 27 taken as 2 + 7, which is 9, and 3 + 3 + 3, which is also 9.

For the number 27: 2 + 7 = 3 + 3 + 3

Can 71 be a Smith Number?

References:

Caldwell, C. (2013). Smith number from The Prime Glossary http://primes.utm.edu/glossary/xpage/SmithNumber.html Accessed 11 June 2013.

Hoffman, P. (1998). The man who loved only numbers: The story of Paul Erdos and the search for mathematical truth. New York: Hyperion.

Weisstein, Eric W. “Smith Number.” From MathWorld–A Wolfram Web Resource. http://mathworld.wolfram.com/SmithNumber.html Accessed 11 June 2013.