Answer:
-2/45
Step-by-step explanation:
-4/9 is simplified and both 4 and 9 are perfect squares.
-8/20 can be reduced to -2/5 since both 8 and 20 are divisible by 4.
The difference between them is given by -4/9 - (-2/5) = (18-20)/45 = -2/45.