4 2/3-5/9*2 4/7 ____________+0,8*1,25; (2 1/7+1 2/3):5

(2 1/7+1 2/3):5№11) 5/9 * 2 4/7 = 5/9 * 18/7 = 10/7 = 1 3/7;2) 0,8 * 1,25 = 1;3) 4 2/3 - 1 3/7 = 14/3 - 10/7 = (14 * 7 - 10 * 3)/21 = (98 - 30)/21 = 68/30 = 2 8/30;4) 2 8/30 + 1 = 3 8/30.Ответ: 3 8/30.№21) 2 1/7 + 1 2/3 = 15/7 + 5/3 = (15 * 3 + 5 * 7)/21 = (45 + 35)/21 = 80/21 = 3 17/21;2) 3 17/21 : 5 = 80/21 : 5 = 80/21 * 1/5 = 16/21.Ответ: 16/21.