[Tutor] Is there a better way to use scientific notation in an equation?

[David Hutto]

In the following code I'm trying to do basic calculations with coulumb's law

#Coulombs Law
'''
F = (9*(10**9)) * (Q1*Q2) / (d**2)
'''
base = 10
Q1mult = raw_input('First enter multiplier of base 10 charge/coloumb(Q1):')
Q1exp = raw_input('Now enter exponent of base 10(Q1):')
Q1 = int(Q1mult)*(10**int(Q1exp))
Q2mult = raw_input('First enter multiplier of base 10 charge/coloumb(Q2):')
Q2exp = raw_input('Now enter exponent of base 10(Q2):')
Q2 = int(Q2mult)*(10**int(Q2exp))
d = raw_input('Enter distance of charges/coulumbs from Q1 to Q2:')



a = (9*(10**9))*((int(Q1))*(int(Q2)))/((int(d))**2)
print a
**********************************************************

Q1 and Q2 are to be entered as base ten scientific notation.
When I try to input Q1 as raw input, entering in ((2*(10**7)), I get:

ValueError: invalid literal for int() with base 10: '((2)*(10**7))'

Which is why I broke it down into it's sub-components(i.e. what to
multiply the base 10 by[Q1mult] and what exponent to use with the base
10[Q1exp]).

Is there a better way to write this, and what would be the best way to
insert the
scientific notation if not this way. I know there is probably a
module, but this is
for my own practice.

TIA
David