Answer:
13/40
Explanation:
We can find the lowest common multiple of 8 and 10, so that the two fractions will have the same denominator.
The LCM of 8 and 10 is 40, so we can rewrite 5/8 as 25/40 by multiplying the numerator and denominator by 5, and rewrite 3/10 as 12/40 by multiplying the numerator and denominator by 4.
This makes the subtraction easier, as we find 25/40 - 12/40.
We get (25-12) / 40, or 13/40.