Solve if you are genius !!!

Right answer is : 6.

Pattern were as follow

8*7=56

7*6=42

6*5=30

5*4=20

4*3=12

3*2=6

2nd pattern to reach at a answer were as follow

8=56

7*2=14 less from 56 then

7=42

6*2=12 less from 42 then

6=30

5*2=10 less from 30 then

5=20

4*2=8 less from 20 then 

4=12

3*2=6 less from 12 then

3=6

There is 3rd pattern as well which is even more difficult but answer justifies as 6, 

Thanks for your participation....