$$$\sum_{n=1}^{25000} n$$$

求$$$\sum_{n=1}^{25000} n$$$。

Since the bounds are finite, the number of terms is finite as well, and we just calculate the sum by summing up the terms.

$${\color{red}{\left(\sum_{n=1}^{25000} n\right)}}={\color{red}{\left(312512500\right)}}$$

Hence,

$$\sum_{n=1}^{25000} n=312512500$$

$$$\sum_{n=1}^{25000} n = 312512500$$$A