How to use distributive property to find 12 + 20 ?

The distributive property states that  

a*(b + c) = a*b + a*c  

You can use the distributive property in reverse to factor out a common factor from the sum of 2 numbers.  If you realize that 12 = 4*3 and 20 = 4*5 then you can write  

12 + 20 = 4*3 + 4*5 = 4*(3 + 5)

probably .5

i can on others if necessary.