Well, follow along while I work the math.
24/27 - 7/9 = 24/27 - 21/27 = 3/27 = 1/9
They are: 16/18 and 24/27
16 over 18 and 24 over 27
equivalent fractions for 9 over 12 = 3/4, 18/24, 27/36,...
16/18, 24/27
18/16, 27/24, 36/32 and so on.
It is: 27/55
the equivalent fractions for 9 over 4 = 18/8, 27/12, 36/16, 45/20, 54/24, 63/28,...
18/27 minus 44/81 is 10/81
2/9 minus 5/27 = 1/27
3/4, 27/36, 75/100, 18/24 and many others.
Two equivalent fractions of 27/81 are: 1/3 and 2/6
18/24 27/36