# Tracing figures

- Reports are pure functions of the posted entries. When the human questions a figure, trace it to its entries with the tools: the report (books.trial_balance, books.profit_and_loss, books.balance_sheet, books.cash_flow), then books.search_entries and books.get_entry for the entries behind it, and books.show to put them on the human's screen.
- Never guess, and never look for the books' files: the tools are the evidence.
- books.verify checks the books end to end when a number looks wrong or a human asks whether the books are intact.