Choose ranges from the question you need to answer
Start from a syllabus item or a missed practice question. Find where the concept is defined, then locate the example and any figure or answer key it refers to. An excerpt that contains the question but omits its diagram or assumptions will give you less to work with later.
Match printed page labels to the PDF viewer
PDF viewers often count covers and contents pages, while the printed numbering starts later. Check the first and last page by heading before extracting the range. Keep the original file and use its name and viewer page numbers in the excerpt's title or a note next to it.
Open the excerpt and verify it before practising
Look at the exported file to check page order, equations and diagrams. Try selecting a sentence if you plan to extract text. A scanned page may require transcription. Pick one question the excerpt can answer and write down the original page where you can check the result.
Worked example
The printed notes place a graph on page 12 and its explanation on pages 13–14. The viewer shows those as pages 16–18 because the file has four pages of front matter. A worked answer on viewer page 22 uses that graph. Export 16–18 and 22, then note the ranges alongside the name of the original PDF.
Before you finish
- Verify both ends of each selected range.
- Keep diagrams, definitions and the answer key when needed.
- Save enough source information to return to the original.