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

### Instruction:
 有1,800条鱼向西游，3,200条鱼向东游，还有500条鱼向北游。如果渔民捕捉了游向东方的鱼的2/5和游向西方的鱼的3/4，那么海中剩下的鱼的数量是多少？


### Response:
 让我们计算游向东方的鱼的数量：3,200 + 500 = <<3200+500=3700>>3,700
游向东方并被捕捉的鱼的数量是3,700 x 2/5 = <<3700*2/5=1480>>1,480
游向西方并被捕捉的鱼的数量是1,800 x 3/4 = <<1800*3/4=1350>>1,350
海中剩下的鱼的数量是3,700 - 1,480 - 1,350 = <<3700-1480-1350=870>>870