Hi there!
To see which fraction is greater, I like to divide the numerator by the denominator of each of the fractions, and then see which decimal is larger. I'll show you what I mean. :)
9 ÷ 10 = 0.9, right? Set this answer aside.
5 ÷ 6 = 0.83
Now, we compare the two fractions. If you are having trouble setting them aside from one-another, multiply the decimals by 100 to see what your percent will be.
0.9 × 100 = 90
0.83 × 100 = 83
So, we now see that 9/10 was greater than 5/6. You were right!
Hope this helps! :D
Message me if you need anything else, I would be happy to help!