А) - 2/3 * 3/4 * (-4/5) б) 3 * (-2/5) * (-5/9) в) - 8 : 3/5 * 9/10 г) - 4/9 * 3/8 : (-2)

А) - 2/3 * 3/4 * (-4/5) = 2/3 * 3/4 * 4/5 = (2 * 3 * 4)/(3 * 4 * 5) = 2/5;

б) 3 * (-2/5) * (-5/9) = 3 * 2/5 * 5/9 = (3 * 2 * 5)/(5 * 9) = 6/9 = 2/3;

в) - 8 : 3/5 * 9/10 = - 8 * 5/3 * 9/10 = - (8 * 5 * 9)/30 = - (8 * 9)/6 = - 12;

г) - 4/9 * 3/8 : (-2) = 4/9 * 3/8 * 1/2 = (4 * 3)/(9 * 8 * 2) = 1/(3 * 2 * 2) = 1/12.