Use each of the num bers 1, 3, 4, and 6 exactly once with any of the four basic m ath operations (addition, subtraction, m ultiplication, and division) to total 24. Each num ber m ust be used once and only once, and you m ay define the order of operations; for exam ple, 3 * (4 + 6) + 1 = 31 is valid, however incorrect, since it doesn't total 24.