Math
posted by Nate on .
What is a shortcut for finding the sum of all numbers from 199?

There is quite the easy shortcut for adding any set of numbers from 1 to whatever and that is this:
(n(n+1))/2
So, let's say you wanted to find the sum of all numbers from 1 to 99. 99 will be n and so the equation will look like the following:
(99(99+1))/2
Solve for the top first:
9900/2
Finish the solution:
9900/2 = 4950
And there you go, you can use and number greater than one as your n.