Euler #20: Factorial Digit Sum

Calculating digit sums of really big numbers sounds daunting. But it is not so with Python and its support for really big numbers. I’m talking numbers like 100! Numbers that far exceed the number of atoms in the known universe.

Euler #11: Largest Product in a Grid

What is the largest product of 4 adjacent numbers of a grid in the 8 compass directions? How do we avoid falling outside of the grid where there dragons be?

Euler #8: Largest Product in a Series

Slide open a window and inhale the crisp air of freshly minted products. Of numbers, that is. The exercise is to find the thirteen adjacent digits in a 1000-digit number that have the greatest product.

Euler #5: Smallest Multiple

“Base prime” is a nifty shortcut used here to calculate the least common multiple of a set of numbers. Imagine a giant Venn diagram of overlapping factors.

Euler #4: Largest Palindrome Product

Never odd or even. Oozy rat in a sanitary zoo. Taco cat. A nut for a jar of tuna. Palindromes are cool. Instead of palindromic sentences, how about palindromic numbers?

Euler #3: Largest Prime Factor

Composite numbers are sieved out, while prime numbers fall through. Check out this totally amateur implementation of the Sieve of Eratosthenes.

Euler #1: Multiples of 3 and 5

Why code when you can sum? Although Project Euler aims to develop programming skills, their first problem doesn’t need it at all. Read more to find out how!