1 7/15 - 4/25 = 1 35/75 - 12/75 = 1 23/75,
6 3/4 * 1 7/9 = 27/4 * 16/9 = 4 * 3 = 12,
3 1/5 : 2 2/5 = 16/5 : 12/5 = 16/5 * 5/12 = 16/12 = 4/3 = 1 1/3,
(48 : 45 - 1/3) * 2 2/11 + 3/5 =
= (48/45 - 15/45) * 24/11 + 3/5 =
= 33/45 * 24/11 + 3/5 =
= 72/45 + 27/45 =
= 99/45 = 11/5 = 2 1/5