When i double my number and add eight, i get my number plus twelve. what is my number?

Let say the number = x

double my number and add eight, I get my number plus twelve

double x and add eight, I get x plus twelve

2x + 8 = x + 12            (subtract x from each side)

2x - x + 8 = 12

x + 8 = 12                (subtract 8 from each side)

x = 12 - 8

x = 4

Your number is 4