To simplify the expression 6 5/8 - 2 1/2, we need to first convert the mixed numbers to improper fractions and then find a common denominator to subtract them.
6 5/8 = (8 × 6 + 5) / 8 = 53 / 8
2 1/2 = (2 × 2 + 1) / 2 = 5 / 2
Now we find a common denominator, which is 8 × 2 = 16.
53 / 8 - 5 / 2 = (53 × 2 - 5 × 8) / (8 × 2) = (106 - 40) / 16 = 66 / 16
The fraction 66 / 16 can be simplified by dividing both the numerator and denominator by their greatest common factor, which is 2.
66 / 16 = (2 × 33) / (2 × 8) = 33 / 8
Therefore, 6 5/8 - 2 1/2 = 33 / 8, or in mixed number form, 4 1/8.