For seven it wants to know how many girls there are in total. That just means it wants you to count all the dots because each dot represents a girl and the line they are over represents the # of headbands they own pretty much. so there are 18 girls.
For 8 they want you to find the number of headbands. so one girl own 4 head bands. 2 other girls own 5 headbands. so 4+5+5. on and on untill u have added all the headbands. Do you get it? I'm gonna let you count the headbands and if you really can't figure that out ill try to help again :)
Hope that helped