To solve this problem, we need to follow the order of operations (parentheses, exponents, multiplication and division from left to right, and addition and subtraction from left to right).

First, let's simplify the expression step by step:

-24/36 (-3/4) (-2/9)
= -2/3 -3/4 -2/9
= -2/3 3/4 2/9
= -6/36
= -1/6

-2/3 5/6 (-9/10)
= -10/18 * -9/10
= 90/180
= 1/2

Therefore, the final answer is:

-1/6 - 1/2
= -4/12 - 6/12
= -10/12
= -5/6

So, the simplified expression is -5/6.