1 + 2-3-4 + 5 + 6-7-8 +. Take two positive and two negative integers from 1. What is the sum of the first 2006 numbers?

1 + 2-3-4 + 5 + 6-7-8 +. Take two positive and two negative integers from 1. What is the sum of the first 2006 numbers?

(1,2,3,4), (5,6,7,8)... So that every four numbers are a group, two positive and two negative are equal to (- 4). Use 2006 / 4 = 501 more than 2, that is to say, there are 501 groups of such four numbers, and there are 2005 and 2006 left. At the same time, 2005 and 2006 should be the first two numbers of the next group, and take positive according to the rule. Multiply the complete 501 group by the number of each group of each group, that is 501 * (- 2) = - 2004. Finally, use - 2004 + 2005 + 2006 = 2007