During Navarathri, we perform puja to Durga Parameswari, the Parasakthi, Mahalakshmi and Saraswati. Whether we talk of them as three murthis or thirty three crores murthis, all of them are only one Parashakthi.
It she this truth is conveyed by Lalitha Sahasranamam while describing the Para Devata (the supreme Devatha) as: She is the one who creates (Srushti Karthari – Brahma Rupa), She is the one who cares our destruction – Samharam. (Samharini Rudra Rupa).
The name Shakthi which is Lalitha and Durgai is also Mahalakshmi and Saraswathi. Ashtothram too, Brahma Vishnu Sivathimikarayi Namaha occurs.
These make clear to us that it is only Sakthi that creates, protects and destroys. Only one Parasakthi wears different make ups and carries out different functions. As Durga, she gives valour, Shakthi, as Mahalakshmi she gives wealth and as Saraswati she give Jnana.