Question

How to calculate the sum (1+2)+(2+3)+(3+4)+...(2012+2013)+(2013+2014)?

Answer 1

`4056195`

Explanation:

This sum has `2013` bracketed terms, with average value:

`((1+2)+(2013+2014))/2 = 2015`

So the sum is:

`2013 * 2015 = 2014^2-1 = 4056195`