For adding, subtracting, and comparing fractions, it is suitable to adjust both fractions to a common (equal, identical) denominator. The common denominator you can calculate as the least common multiple of both denominators - LCM(8, 6) = 24. In practice, it is enough to find the common denominator (not necessarily the lowest) by multiplying the denominators: 8 × 6 = 48. In the following intermediate step, the fraction result cannot be further simplified by canceling.
In other words - five eighths minus one sixth = eleven twenty-fourths.