1) = (3 19/24 + 1 5/24) + 5 1/9 = 4 24/24 + 5 1/9 = 5 + 5 1/9 = 10 1/9;
2) = (1 5/8 + 2 3/8) + (4 8/17 + 9/17) = 3 8/8 + 4 17/17 = 4 + 5 = 9;
3) = (7 16/35 - 3 11/35) - 4 1/56 = 4 5/35 - 4 1/56 = 4 1/7 - 4 1/56 = 4 8/56 - 4 1/56 = 7/56 = 1/8;
4) = ( 4 56/789 - 4 56/789) + 1 23/456 = 0 + 1 23/456 = 1 23/456
