link to the balance-sheet cash line
Picture a piggy bank. At the start of the year it held 10,000. Over the year, coins went in and coins came out, and a running tally of every in-and-out movement should, by simple arithmetic, leave the bank holding exactly what you find when you finally tip it out and count. The cash flow statement is the running tally; the balance sheet's cash figures are the count at each year-end. They must agree — that agreement is the link.
Concretely, the cash flow statement adds operating, investing, and financing cash flows to get the net change in cash for the period. That net change, added to the beginning cash and cash equivalents (the figure shown on last year's balance sheet), must equal the ending cash and cash equivalents (the figure on this year's balance sheet). For instance: beginning cash 10,000 + net change 5,000 = ending cash 15,000, and that 15,000 is exactly the cash line you see on the year-end balance sheet.
This tie-out is a built-in check that the statement is internally consistent and that no cash flow has been lost or double-counted; it is one of the first things a preparer or auditor verifies. It also shows how the three core statements 'articulate' — they are not independent reports but interlocking views of the same business. If the cash flow statement's ending figure does not match the balance sheet's cash line, something is wrong and must be found before the statements can be trusted.
Last year's balance sheet showed cash and cash equivalents of 10,000. This year the cash flow statement reports net change in cash of +5,000, so ending cash must be 15,000 — and indeed this year's balance sheet shows exactly 15,000 on its cash line.
Beginning cash + net change = ending cash, matching the balance sheet exactly.
The figure that must tie out is cash AND cash equivalents combined, not just the 'cash' line alone — if equivalents are reported on a separate line, both must be included to make the link work.