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?
Nate had read 400 x 20/100 = <<400*20/100=80>>80 pages.
So, he still needs to read 400 - 80 = <<400-80=320>>320 pages to finish the book.
#### 320