' ' hexadecimal values are prefaced with xoctal values are prefaced with and binary values are prefaced with the int function the int function has an optional second argument that allows you to specify the base you are converting from here are few examplesint' ' int' ' int' ' int' ' convert from base convert from base convert from base convert from base the pow function python has built-in function called powwhich raises numbers to powers it behaves like the *operatorexcept that it takes an optional third argument that specifies modulus thus pow( , ,nreturns ( ** )% the reason you might want to use this is that the pow way is much quicker when very large numbers are involvedwhich happens lot in cryptographic applications using the python shell as calculator often use the python shell as calculator this section contains few tips for working at the shell importing math functions one good way to start session at the shell is to import some math functionsfrom math import special variable there is special variable which holds the value of the previous calculation here is an example ** +