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

### Instruction:
 内特开始他的野营之旅时有70根火柴。他在小溪里掉了10根，他的狗吃了两倍的数量。他还剩下多少根火柴？


### Response:
 首先找出狗吃掉的火柴数量：10根火柴 * 2 = <<10*2=20>>20根火柴
然后从起始数量中减去所有丢失的火柴，找到最终数量：70根火柴 - 20根火柴 - 10根火柴 = <<70-20-10=40>>40根火柴