1) no one helps these students to do those exercises 
---> these students  do those exercises themselves 
2) nobody helps her wash her clothes 
---> she  washes her clothes herself 
3) no one helped him do the exercises 
---> he  do the exercises  himself 
4) i made this jumper on my own 
--->  i made this jumper myself 
5) we put up the tent on our own 
---> we put up the tent ourselves 
6) the dog sleeps on its own in the kitchen 
---> the dog sleeps itself  in the kitchen