Project Euler facts for kids
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Type of site
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Problem Solving Website |
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| Created by | Colin Hughes |
| Website | projecteuler.net |
| Commercial | No |
| Registration | Free |
| Launched | October 5, 2001 |
Project Euler is a fun website for anyone who loves mathematics and computer programming. It's named after a famous mathematician, Leonhard Euler. The site gives you tricky math and computer puzzles to solve using your own computer programs.
Colin Hughes started Project Euler in 2001. Since then, it has become super popular all over the world. There are over 700 puzzles, and a new one appears every week or two! These puzzles have different difficulty levels. You can solve each one in less than a minute if your computer program is smart and fast. By April 2020, over 1,000,000 people worldwide had solved at least one puzzle on Project Euler.
Contents
What You Can Do on Project Euler
Project Euler has many cool features that make solving problems even more exciting.
Forums and Progress Tracking
- Discuss Solutions: After you solve a puzzle, you can see a special discussion forum for that specific problem. This is a great place to learn how others solved it!
- Sort Problems: You can sort the puzzles by their ID number, how many people have solved them, or how hard they are.
- Track Your Journey: The site helps you see how well you're doing. You earn new achievement levels for every 25 puzzles you solve.
Special Awards and Challenges
- Earn Awards: There are special awards for solving certain groups of puzzles. For example, you can get an award for solving fifty puzzles that have prime numbers as their ID.
- "Eulerians" Level: This special level lets newer members compete. It tracks the fifty fastest people to solve the newest puzzles. This way, you don't have to solve all the old puzzles to be a top solver!
Try a Project Euler Puzzle
Let's look at the very first puzzle from Project Euler. It's simpler than most, but it shows how important it is to find a clever way to solve problems.
The First Puzzle
The problem asks:
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.
Solving the Puzzle: Two Ways
There are different ways to solve this puzzle using a computer program.
Simple (Brute-Force) Method
One way is to check every single number from 1 up to 999. If a number can be divided by 3 or 5, you add it to a running total. This is called a "brute-force" method because it checks every possibility. It's easy to understand and program:
total := 0 for NUM from 1 through 999 do if NUM mod 3 = 0 or NUM mod 5 = 0 then total := total + NUM return total
Smarter (Efficient) Method
For harder puzzles, just checking every number can take too long. You need a more "efficient" way. For this puzzle, you can use a math trick called the inclusion–exclusion principle. This trick helps you count things without counting them twice. You can also use a special math formula to quickly sum up numbers.
This smarter method uses much less computing power. It's like finding a shortcut instead of walking the long way around!
See also
In Spanish: Project Euler para niños
