Help me this is a very very big question!! Please find the number patterns
1. 80,40,20 _,5
2. 7,5,15,13,39,_,_
3. 90,30,180,_,360,120
4. 15,25,45,_,115,165
5. 56,60,20,24,_, 12,4
6. 6.5,5.5,4.5,3.5, _, _
7. 15,14,12,_,5,0