Sequence 1. - 2,3, - 4 ,99,-100,… What are the top 200 items and?

Sequence 1. - 2,3, - 4 ,99,-100,… What are the top 200 items and?

grouping:
(1,-2),(3,-4),…… (- 199200), a total of 200 / 2 = 100 groups, the sum of each group is equal to - 1
Top 200 items and = (- 1) × 100 = - 100