a)
1 9/11 + 2 3/11 = (1+2) + (9/11 + 3/11) = 3 + 12/11 = 3 + 1 1/11 = 4 1/11
б)
3 2/9 + 1 7/9 = (3+1) + (2/9 + 7/9) = 4 + 9/9 = 4 + 1 = 5
в)
4 1/3 - 2 2/3 = 13/3 - 8/3 = (13-8)/3 = 5/3 = 1 2/3
г)
26 2/5 - 17 3/5 = 25 7/5 - 17 3/5 = (25-17) + (7/5 - 3/5) = 8 + 4/5 = 8 4/5
д)
8 2/7 - 3 4/7 = 7 9/7 - 3 4/7 = (7-3) + (9/7 - 4/7) = 4 + 5/7 = 4 5/7