Use Gauss’ formula: sum = 1000/2 *(1000+2) = 250500

Hi Rima, I slightly disagree with your answer. Firstly, the formula for sum of natural number is 1/2n(n+1). Secondly, sum of natural number is 1+2+3+4+5+...., the situation here is sum of even number between 1 and 1000, so the summation formula here doesn't really work.

There are two methods to do this question:

Method 1: this sequence is 2+4+6+....+1000, so it is an arithmetic sequence. The fo... more

The equation for figuring out the sum of natural numbers is n(n+1).

The n stands for how many numbers are actually even within that series of 1-1000.

We know that there are 500 numbers that are even between 1-1000 therefore n=500. We can then plug 500 into our equation.

500(500+1)

=500 x 501

=250500