(12 целых 1/3 - 7 целых 3/4) * 6/11 = 2 целых 1/2
1) 12 1/3 - 7 3/4 = 12 4/12 - 7 9/12 = 11 16/12 - 7 9/12 = 4 целых 7/12
2) 4 7/12 * 6/11 = 55/12 * 6/11 = (5*1)/(2*1) = 5/2 = 2 целых 1/2
Пояснения:
1/3 = 4/12 - доп.множ. 4
3/4 = 9/12 - доп.множ. 3
4 целых 7/12 = (4*12+7)/12 = 55/12