a) 17/35 + 18/35 = (17 + 18) / 35 = 35/35 = 1
б) 24/27 - 4/9 = 24/27 - (4 * 3)/(9 * 3) = 24/27 - 12/27 = (24 - 12) / 27 = 12/27 = 4/9
в) 9/4 * 20/18 = (9 * 20) / (4 * 18) = (9 * 4 * 5) / (4 * 9 * 2) = 5/2 = 2,5
г) 24/48 : 3/8 = 24/48 * 8/3 = (24 * 8) / (48 * 3) = (24 * 8) / (24 * 2 * 3) = 8 / (2 * 3) = 4/3 = 1 1/3
д) 9 7/13 - 5 3/13 = (9 - 5) + (7/13 - 3/13) = 4 + 4/13 = 4 4/13
е) 1,4 : 2 + 3/10 = 0,7 + 0,3 = 1
Ответ: а) 1; б) 4/9; в) 2,5; г) 1 1/3; д) 4 4/13; е) 1