For solving these kinds of problems first check the degree of unsaturation. If it is non zero then at once draw all possible structure (carbon skeleton only) of corresponding alkane and then check all the possibilities of putting the π bond. To find the cyclic isomers, start with the 3 membered ring.
Possible acyclic carbon skeletons are
Total 5 acyclic structural isomers are possible
Possible Cyclic structures are
Total 5 cyclic isomers are possible.
Total structural isomers possible are 10.
