.5 as a fraction is 1/2 and .005 as a fraction is 5/1000. You need to find a common denominator. To get the 2 in 1/2 to 1000 you multiply by 500. You do the same to the numerator. So 1 x 500 = 500. So it would read 500/1000. Add these 2 fractions together to get 505/1000. Simplify to 101/200.