i need some help

i need some help   (06/08/2010, 1:26 AM)

i am interested in some calculation (multiply them) about measurement units such as:

(5 meters) * 5 meters = 25 m2
2 candelas) * 3 lumen = 6 cd2
(5 pascals) * 4 pascals = 20 m-2 kg2 s-4

someone knows why is the result is m-2 kg2 s-4 when u multiply pressure unit and can point me to a conversion table that explains that.