Learn why coin and currency on hand, ordinary checks, and demand-deposit balances are cash. Then apply the cash-equivalent tests for short-term, highly liquid investments, including conversion to a known amount of cash and insignificant interest-rate risk. Use the general three-month original-maturity screen measured from acquisition, together with the other tests and the company's policy. A customer-receivable counterexample and certificate-of-deposit examples show why timing alone is not enough.