[
  "Draw a bar model: first find the current number of non-fiction books. Then find the target number.",
  "Fiction = 8 units = 1800, so 1 unit = 1800 / 8 = 225. Non-fiction now = 225 books. Target = half of fiction = 1800 / 2 = 900.",
  "Additional non-fiction needed = 900 - 225 = 675 books."
]