25 5/8 - 11 5/6 = 13 19/24
Subtracting or adding fractions requires that they have the same denominator. You do this by finding the LCM and cross multiplying, including the numerators. The LCM of 8 and 6 is 24, so the problem becomes 25 15/24 - 11 20/24 = 13 19/24. Since 19 is prime, and 24 is not relatively prime to 19, the solution can not be reduced any further.
55
88...
275
It is 198 which is also the LCM
The only common factor is: 1
44
77
88
55
It is: 1925
It is: 220
88...
22
It is: 1
176
44
The LCM is: 231