You can't simplify 5/6 since while 6 would divide in half to be 3 and match the other denominator, 5 wouldn't divide in half evenly. Instead, multiply the top and bottom number of the other fraction by two:
5/6 - 4/6
This way they share equal denominators. When subtracting fractions with matching denominators, the denominator doesn't change in the answer. Just subtract the numerators:
If you take 369 divided by 410 it gives you 0.9 which is equal to 90% which then leads us to realized that if 369 is 90% of 410 then the discount would have to be 10%
