Multiples of 3 or 5
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.
Writing
Euler-project
Notes on engineering, product work, leadership, and the practical details that make software better.
Sum square difference
The sum of the squares of the first ten natural numbers is
Summation of primes
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.