how can i calculate two currency fields?

[Sachin65]

 i need to calculate two currency fields. 

field name: u_currency1 (type currency)   

field two name:  u_currency2 (type currency) 

  field 3 name: u_store : (type choice ) 

my req is

u_currency1 /  u_currency2 *100 basced on this value set the choice field 

[Omkar Mone]

Hi 

I forgot to add the code....thanks.