What do you mean? 9%=.9 + 9%=.9 =18%=.18
18% of $10,000 is $1,800 hence $10,000+$1,800=$11,800
Did you mean math fail for you?
Your logic is sound, I’m just nitpicking.
10,000 x .18 = 1,800
10,000 + (10,000 x .18) = 11,800