Total number of stereoisomers of 1,2-dimethyl-4-(propan-2-ylidene)cyclopentane
Here is a similar molecule to illustrate: 

Two of the ring carbons are asymmetric (chiral). This molecule itself (as shown) is chiral. If you change one of the chiral carbons, you get a molecule that is not chiral (mirror plane along the double bond and perpendicular to the ring).