assign value

i want to assign a value to a character or string

like i have formula p2p3= (n-1)*p +(2*e)

i want to assign values(number) to n,p,e.............so that i can get p2p3....like want to assign 'n'=4
i dnt want to use cell number for calling values of n,p,e

help me out fast

Try using please & named ranges.