А) 2 * (14/15 : 2/3) = 2 целых 4/5
1) 14/15 : 2/3 = 14/15 * 3/2 = (7*1)/(5*1) = 7/5
2) 2 * 7/5 = 14/5 = 2 целых 4/5
б) 12/11 : 3/4 * 11/24 = 2/3
1) 12/11 : 3/4 = 12/11 * 4/3 = (4*4)/(11*1) = 16/11
2) 16/11 * 11/24 = (2*1)/(1*3) = 2/3
в) 1/2 * 2/3 * 3/4 * 5/4 = (1*2*3*5)/(2*3*4*4) = (1*5)/(4*4) = 5/16