The fifth Power of Three book is called Long Shadows
The fourth book in the Power of Five series is called "Necropolis."
Necropolis
(city of the dead)
Sunrise.
Eclipse
Nightrise
the sight
Ravens Gate
Evil Star
As of now, there are no officially announced plans for another book in the "Power of Five" series by Anthony Horowitz. However, the author may choose to continue the series in the future.
five, though there is a first book, second book, third book, into the mist, and the fourth book.
It was released in Autumn 2012.
its 5 to the 4th power times 5 to the fourth power and the answer is 390625
12,207,031
The Answer is 656
Autumn 2012 (October)
They all have different names. The first series is called the Original Series, the second is called The New Prophecy, and the third The Power of Three. Erin Hunter is coming out with a new series called the Omen of the Stars. There is only one book out yet in that series which is called The Fourth Apprentice. I think you're talking about a series as in trilogy, saga, or quintet. I don't know the name of anything other than that, but I just wanted to clear that up.
There hasn't even been a fourth series yet.
54 = 625.