I saw your other post too. You can't round this because rounding changes the #.
The best way to solve is to multiply by a fraction that is equivalent to 1, such as multiplying 1/2 x 1.9/1.9 which is 1.9/3.8, now multiply 1/1.9 x 2/2 which is 2/3.8
2/3.8 - 1.9/3.8 is the same as 2-1.9 / 3.8 = 0.1/3.8