Выполните действия: (1 3/7+4 5/21-5 1/4)*1 5/7+8 1/4:2 5/8 помогите плиз

Приведем смешанные дроби к виду обыкновенных. 1) 1 3/7 = (7+3)/7 = 10/7 = 30/21;2) 4 5/21 = (4*21+5)/21 = (84+5)/21 = 89/21;3) 5 1/4 = (5*4+1)/4 = 21/4;4) 1 5/7 = (7+5)/7 =12/7;5) 8 1/4 = (8*4+1)/4 = 33/4;6) 2 5/8 = (2*8+5)/8 = 21/8;(30/21 + 89/21 - 21/4)*12/7 + 33/4 : 21/8 = 119/21 * 12/7 - 21/4 * 12/7 + (33 * 8)/(4 * 21) = 17/3 * 12/7 - (21 * 12)/(7 * 4) + 33 * 2/21 = 17*4/7 - 3*3 + 22/7 = (68+22)/7 - 9 = 90/7 - 9 = 90/7 - 63/7 = 27/7.Ответ: 27/7.