Б)1 1/5*3+4/5*3 в)2 4/5*3-4/5*3 г)2 4/5*5/+6 1/5*5/9

б) 1 1/5 * 3 + 4/5 * 3 = 6/5 * 3 + 12/5 = 18/ + 12/5 = 30/5 = 6;

в) 2 4/5 * 3 - 4/5 * 3 = 14/5 * 3 - 12/5 = 42/5 - 12/5 = 30/5 = 6;

г) 2 4/5 * 5 + 6 1/5 * 5/9 = 14/5 * 5 + 31/5 * 5/9 = 14/1 * 1 + 31/1 * 1/9 = 14/1 + 31/9 = 

= 126/9 + 31/9 = 157/9 = 17 4/9.