Okay first you need to change the fractions into an improper fraction. So 8 5/6 become 53/6 ( multiply 6 and 8 then add 5), and 2 4/9 becomes 22/9(multiply 9 and 2 then add 4). Next you need to find a common denominator that 6 and 9 can go into which is 18. So you multiply the improper fractions by numbers that will make your denominator 18. Multiply 53 and 6 by 3 , and multiply 22 and 9 by 2. Your new fractions should be 159/18 and 44/18. Then you subtract the numerators and keep the denominator the same. The answer is 115/18. You can convert it back to a mixed number if you want. - Nae