7/10 * 2 3/7 - 0,1 : (2 1/5 : 2 1/4 - 1,3 : 2 1/4) = 1,45
1) 2 1/5 : 2 1/4 = 11/5 : 9/4 = 11/5 * 4/9 = 44/45
2) 1,3 : 2 1/4 = 13/10 : 9/4 = 13/10 * 4/9 = 52/90
3) 44/45 - 52/90 = 88/90 - 52/90 = 36/90 = 2/5
4) 7/10 * 2 3/7 = 7/10 * 17/7 = 17/10 = 1,7
5) 0,1 : 2/5 = 1/10 * 5/2 = 5/20 = 1/4 = 0,25
6) 1,7 - 0,25 = 17/10 - 1/4 = 34/20 - 5/20 = 29/20 = 1 9/20 = 1,45