Task: Find the sum of all the multiples of 3 or 5 below 1000.

Task: By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

Task: What is the largest prime factor of the number 600851475143 ?

Task: Find the largest palindrome made from the product of two three-digit numbers.

Task: What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

Task: Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

Task: What is the 10 001st prime number?

Task: Find the greatest product of five consecutive digits in the 1000-digit number.

Task: There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product abc.

Task: Find the sum of all the primes below two million.