1 - 17/30 - 11/30 = 1 - (17+11)/30 = 1 - 28/30 = 1 - 14/15 = 15/15 - 14/15 = 1/15
1 - 10/11 = 1 - (10/11 * 11/11) = 1 - 10/11 = 1/11
1 - 17/30 - 11/30 = 1 - (17+11)/30 = 1 - 28/30 = 1 - 14/15 = 15/15 - 14/15 = 1/15
1 - 10/11 = 1 - (10/11 * 11/11) = 1 - 10/11 = 1/11