Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 道琼斯工业平均指数今天下跌了2%。道琼斯在收盘时为8722点。市场开盘前的道琼斯指数是多少？


### Response:
 今天道琼斯下跌了8722 / 98*2 = <<8722/98*2=178>>178点。
所以开盘时的指数为8722 + 178 = <<8722+178=8900>>8900点。