№ 1.
12 : 3 3/8 - 1 1/4 : 15/32 = 8/9
1) 12 : 3 3/8 = 12 : 27/8 = 12/1 * 8/27 = 4/1 * 8/9 = 32/9 = 3 5/9
2) 1 1/4 : 15/32 = 5/4 * 32/15 = 1/1 * 8/3 = 8/3 = 2 2/3
3) 3 5/9 - 2 2/3 = 3 5/9 - 2 6/9 = 2 14/9 - 2 6/9 = 8/9
№ 2
1 31/35 : (2 - 8/9 : 1 19/45) = 1 13/35
1) 8/9 : 1 19/45 = 8/9 : 64/45 = 8/9 * 45/64 = 1/1 * 5/8 = 5/8
2) 2 - 5/8 = 1 8/8 - 5/8 = 1 3/8
3) 1 31/35 : 1 3/8 = 66/35 : 11/8 = 66/35 * 8/11 = 6/35 * 8/1 = 48/35 = 1 13/35