一组数:1,-2,3,-4,5,-6,…,99,-100,这100个数的和等于_.

问题描述:

一组数:1,-2,3,-4,5,-6,…,99,-100,这100个数的和等于______.

1-2+3-4+5-6+…+99-100=-1-1-1-…-1=-50,
故答案为:-50.