Odpowiedź:
a)
2 3/20 + 1/4 = 2 3/20 + 5/20 = 2 8/20 = 2 2/5
1 5/18 + 2 4/9 + 5/6 = 1 5/18 + 2 8/18 + 15/18 = 3 13/18 + 15/18 = 3 28/18 = 4 10/18
3 1/2 + 2 3/4 + 1 1/3 = 3 2/4 + 2 3/4 + 1 1/3 = 5 5/4 + 1 1/3 = 6 1/4 + 1 1/3 = 6 3/12 + 1 4/12 - 7 7/12
b)
2 1/20 - 3/4 = 1 21/20 - 15/20 = 1 6/20 = 1 3/10
1 7/18 - 2 2/9 = 1 7/18 - 1 11/9 = 1 7/18 - 1 22/18 = 15/18 = 5/6
2 1/7 - 5 2/3 = 2 3/21 - 5 14/21 = -3 11/21
Szczegółowe wyjaśnienie: