Odpowiedź:
5,7 : (5 i 3/7 - 3,8) = 5 i 7/10 : (5 i 3/7 - 3 i 8/10) = 5 i 7/10 : (5 i 30/70 - 3 i 56/70) = 5 i 7/10 : (4 i 100/70 - 3 i 56/70) = 57/10 : 1 i 44/70 = 57/10 * 70/114 = 7/2 = 3 i 1/2
2,5 * 4 i 1/2 - 5 i 17/20 : 0,9 = 2 i 5/10 * 4 i 1/2 - 5 i 17/20 : 9/10 = 25/10 * 9/2 - 117/20 * 10/9 = 225/20 - 13/2 = 225/20 - 130/20 = 95/20 = 4 i 15/20 = 4 i 3/4
2 i 1/2 * 1,3 + 4 i 7/8 : 1,25 = 2 i 1/2 * 1 i 3/10 + 4 i 7/8 : 1 i 25/100 = 5/2 * 13/10 + 39/8 : 5/4 = 13/4 + 39/8 * 4/5 = 13/4 + 39/10 = 65/20 + 78/20 = 143/20 = 7 i 3/20