LearnHub

wmoxam said:

Anybody tried out Project Euler?

http://projecteuler.net

It’s a list of mathematics problems, with a new problem added weekly. I’ve solved ten so far (out of 189!), and they are challenging but fun. Most people use either a general programming language (like ruby) or a math language (such as Maple or Mathematica) to solve the problems, but a few hardcore people use pencil and paper. After providing the correct answer you get access to a discussion board where people share how they arrived at the result.

My public profile can be found at: http://projecteuler.net/index.php?section=profile&profile=wmoxam

Here are a few example questions:

1) If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000.

2) n! means n × (n − 1) × … × 3 × 2 × 1 Find the sum of the digits in the number 100!

3) The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime.

There are thirteen such primes below 100: 2, 3, 5, 7, 11, 13, 17, 31, 37, 71, 73, 79, and 97.

How many circular primes are there below one million?

geof said:

Yeah, a bunch of us worked on it last summer. I was using Excel with VBA.

http://www.vbcity.com/forums/topic.asp?tid=148206&highlight=project%7Ceuler

wmoxam said in response to:

Oh, cool. I never thought about solving these problems with Excel. I imagine that it provide a pretty good math library for VBA to work with.

geof said:

Well, I learned some things that I didn’t know about in VBA, and I thought I was good in VBA.

It was humbling to see some questions solved with 1 or 2 lines where I was taking about 50 lines of code to do it!