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

### Instruction:
Nate is reading a 400-page book. He finished reading 20% of the book. How many pages does he need to read to finish the book?

### Response:
 เนต์อ่านไปแล้ว 400 x 20/100 = <<400*20/100=80>>80 หน้า
ดังนั้น เขาต้องอ่านอีก 400 - 80 = <<400-80=320>>320 หน้าเพื่อจบหนังสือ