(2+4+6+++3+5++2005) the ‘’ means they add up until it gets to 2006 or 2005. plz tell me how you get the answer. i have the answer 1003 but i’m not sure how.!

I will solve the problem by 2 methods.

I will use Gauss's formula for calculating each string, then we will decrease the results.

We find the number of terms of each string.

We intersect the terms in the second string among the terms of the first string.