1/51 и 1/68 = 1/(3*17) и 1/(4*17) = 4/204 и 3/2085/36 и 7/54 = 5/(2*2*9) и 7/(2*3*9) = 15/108 и 14/1089/35 и 11/42 = 9/(7*5) и 11/(7*6) = 54/210 и 55/2104/49 и 5/63 = 4/(7*7) и 5/(7*9) = 36/441 и 35/44115/98 и 13/72 = 15/(2*49) и 13/(2*36) = 540/3528 и 637/3528