1) 6a * (-2b) * (-c) = 12abc 2) -5/6a * (-4/5b) * 3/8 = 2/3ab * 3/8 = 1/4ab 3) -0,5a * (-7b) * (-2c) = - 7abc 4) -4m * 0,8c * (-5d) = 16mcd