Вычислите : 12-11 6/11 , 16 3/13-6 8/13 , 13 4/9-2 8/9

Вычислим значения выражений:

1) 12 - 11 6/11  = 12 - 11 - 6/11 = 1 - 6/11 = 11/11 - 6/11 = (11 - 6)/11 = 5/11; 

2) 16 3/13 - 6 8/13  = 16 + 3/13 - 6 - 8/13 = (16 - 6) + (3/13 - 8/13) = 10 + (3 - 8)/13 = 10 - 5/13 = 9 + 1 - 5/13 = 9 + 13/13 - 5/13 = 9 + (13 - 5)/13 = 9 + 8/13 = 9 8/13; 

3) 13 4/9 - 2 8/9 = 13 + 4/9 - 2 - 8/9 = (13 - 2) + (4/9 - 8/9) = 11 + (4 - 8)/9 = 11 - 4/9 = 10 + 1 - 4/9 = 10 + 9/9 - 4/9 = 10 + (9 - 4)/9 = 10 + 5/9 = 10 5/9.