Find the sum of the integers 1 to 2008?

Answer 1

Answser: 2017036 ---- Here is how and why this works! the sum of the first n integers is n(n+1)/2 To see this, think of 10 numbers, lets write them two ways 1 2 3 4 5 6 7 8 9 10 10 9 8 7 6 5 4 3 2 1 Not that each pair is equa to 11 which is 10+1 and ther are 10 pairs so we have 10x11, but we listed the numbers twice so we need to divide by 2 to adjust for that..

In your question, the answer is 2008(2009)/2=2017036