Question

what is the algorithm for the sum of even numbers up to 50​

Answer 1

The sum would be all natural numbers from 1 to 50. If you multiplied each term in the sum by 2, you'd have all the even numbers from 2 to 100. By the distributive property, the sum of all the even numbers from 1 to 100 is the same as 2 times the sum of all numbers from 1 to 50