Quandaries and Queries Name: Reid Level: Secondary plus, I think Who is asking: Other, guy with a problem who needs a solution Can someone please explain, answer and/or solve this: (220,966,011) - 1 I don't know what it means, my boss sent it out, I'm assuming it is to be solved but don't know what it is, any prompt help would be appreciated, very much so, in fact, thanks,........... Hi Reid, Well, there's nothing to solve really. What it is about is that recently someone showed that if 2 is raised to the 20,966,011 power and then you subtract 1 from the result, what you have is a prime number - a number with no proper divisors (11 is prime but 8 is not, for example). We know that primes can be arbitrarily large but they're hard to find once you get 'up there'. So, this is the largest one that has been identified so far. Who cares? Actually bankers do - large primes are used in cryptography in constructing hard-to-break codes. When transmitting money/info around the world it is important that your messages be secure so tough to break codes are a must. Penny Go to Math Central