jedna trzecia + siedem dwunastych , osiem piętnastych + trzy piąte , trzy piąte + trzy dziesiąte , trzy czwarte - pięć ósmych , jedna czwarta - trzy dwudzieste , siedem dziesiątych - trzy dwudzieste , P.B: jedna trzecia + jedna druga , 3/4 - 2/5 , 5/8 + 1

1/3 + 7/12 = 4/12 + 7/12 = 11/12 8/15 + 3/5 = 8/15 + 9/15 = 17/15 = 1 2/15 3/5 + 3/10 = 6/10 + 3/10 = 9/10 3/4 - 5/8 = 6/8 - 5/8 = 1/8 1/4 - 3/20 = 5/20 - 3/20 = 2/20 = 1/10 7/10 - 3/20 = 14/20 - 3/20 = 11/20 1/3 + 1/2 = 2/6 + 3/6 = 5/6 3/4 - 2/5 = 15/20 - 8/20 = 7/20 5/8 + 1/7 = 35/56 + 8/56 = 43/56 5/6 - 3/7 = 35/42 - 18/42 = 17/42 2/7 + 1/5 = 10/35 + 7/35 = 17/35 7/8 - 2/3 = 21/24 - 16/24 = 5/24 1/9 + 1/7 = 7/63 + 9/63 = 16/63  3/5 - 1/3 = 9/15 - 5/15 = 4/15 7/9 - 3/4 = 28/36 - 27/36 = 1/36 7/9 + 4/5 = 35/45 + 36/45 = 71/45 = 1 26/45 4/5 + 5/8 = 32/40 + 25/40 = 57/40 = 1 17/40 5/7 - 1/6 = 30/42 - 7/42 = 23/40 2/3 - 1/10 = 20/30 - 3/30 = 17/30 1/6 + 6/7 = 7/42 + 36/42 = 43/42 = 1 1/42 3/4 + 4/5 = 15/20 + 16/20 = 31/20 = 1 11/20 5/6 + 5/7 = 35/42 + 30/42 = 5/42 10/11 - 1/2 = 20/22 - 11/22 = 9/22 2/3 - 2/7 = 14/21 - 6/21 = 8/21