The income statement reads top to bottom as a series of subtractions, each answering a different question: revenue for scale and demand, gross profit for the economics of the product itself, EBIT for the cleanest cross-company comparison, and net income — the most manipulable single number on the page.
The balance sheet is a photograph on the last day of the quarter, which is precisely why window-dressing happens in the final week. Book value is a historical-cost artefact: a retailer's 1985 freehold sits at 1985 prices, a software firm's real assets are largely not on the books at all, and goodwill is on the books at exactly what the last CEO overpaid.
The cash flow statement is the reconciliation. Net income flows into retained earnings and into the top of CFO; capex builds PP&E, which depreciates back through the income statement; the change in cash across all three sections must equal the change in the balance sheet's cash line. Profit is an opinion and cash is a fact — but an incomplete one, since cash can be flattered by stretching payables or simply not investing.
Educational, not investment advice.