(21(2/3) – 7(1/6)) / 2,32. 21(2/3) – 7(1/6) = 65/3 – 43/6 = 130/6 – 43/6 = 87/6 = 14,5. 14,5/2,32 = 6,25. Ответ: 6,25. (1(11/18) + 25/36) * 12,8. 1(11/18) + 25/36 = 29/18 + 25/36 = 58/36 + 25/36 = 83/36 = 2(11/36). 83/36 * 12,8 = 83/36 * 64/5 = 5312/180 = 1328/45 = 29(23/45). Ответ: 29(23/45).