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

### Instruction:
 路易在一次数学测验中得了80%。他犯了5个错误。这次数学测验有多少道题目？


### Response:
 路易得了100% - 80% = 20%的题目错误，相当于5道题目。
所以1%相当于5/20 = 1/4道题目。
因此，总共的题目数量，即100%，是100 x 1/4 = 25道题目。