How many gods and goddesses do Hindus believe in?

To know Hinduism it is always better to get a Hindu's answer.

We have only one supreme power as God and this one God manifests in various forms and names to create govern and destroy the unwanted things of this Universe.
Siva, Vishnu, Brahma, Sakthi,Ganesh and Skantha are six major manifestations of the one God forming six sub religions Saivism, Vaishnavism, Ganapathyam,Gowmaram, Saktham and Sowmaram.

Vishnu is always surrounded and praised by 33 crores of angels called Devatas. Only this factor the Abraham religion preachers are wantonly tilting to make a mockery of Hinduism. Since Hindus are not interested in proselytism they left this mischief played by Abraham preachers unnoticed. Only now we come to know about this due to open forums.