In Excel, I can get a string formula for some place.
for example: (P1+P2+P3^2)/3 , P1*2+P4/3, ........

P1, P2,P3,P4 is variant I can its value from some place:
for example: P1 = 1, P2 =2, P3 =3, P4 =4

so I can get the calculated formula as follow: "(1+2+3^2)/3"
my question is: how to convert this string formula to real calculate formula
? so I can get value (1+2+3^2)/3 is 4 ??

I have review all of function of string, can not find a way to do it:(
anyone can help me out ?? thanks a lot!