3 2/15-1 1/7=

5/34-41=

3 1/30-5 7/90 =

6 1/7-10 3/4

3 2/15 - 1 1/7 = 47/15 - 8/7 = (47 * 7 - 8 * 15) / 105 = 329/105 - 120/105 = 209/105 = 1 104/1055/34 - 41 = 5/34-41/1 = (5 * 1 - 41 * 34) / 34 = 5/34 - 1394/34 = - 1389/34 = - 40 29/34

3 1/30 - 5 7/90 = 91/30 - 457/90 = (91 * 3 - 457 * 1) / 90 = 273/90 - 457/90 = - 184/90 = - 92/45 = - 2 2/45

6 1/7 - 10 3/4 = 43/7 - 43/4 = (43 * 4 - 43 * 7) / 28 = 172/28 - 301/28 = - 129/28 = - 4 17/28