5 2/13*7 1/6-20*(3/20-2/5-1/4)-6 2/13*7 1/6

5(2/13) * 7(1/6) – 20 * (3/20 - 2/5 - 1/4) – 6(2/13) * 7(1/6). 7(1/6) * (5(2/13) – 6(2/13)) = 7(1/6) * (-1) = -7(1/6). 3/20 – 2/5 – 1/4 = 3/20 – 8/20 – 5/20 = -10/20 = -1/2. 20 * (-1/2) = -10. -7(1/6) – (-10) = 10 -43/6 = 17/6 = 2(5/6). Ответ: 2(5/6).