Please show me how to subtract mixed numbers

Same denominator or different ones?

I'm assuming you mean a number like 1-1/2 to denote a mixed number?
Let's use an example: (1-1/2)-(2-2/3). (One and a half minus two and two thirds.)
First, convert the fractions to fractions with the same denominator. In this case,
multiply 1/2 by 3/3 to get 3/6. And multiply 2/3 by 2/2 to get 4/6. The resulting
mixed numbers are 1-and-3/6, and 2-and-4/6.

Next, subtract the whole numbers: 1 - 2 = -1.
Second, subtract the proper fractions: 3/6 - 4/6 = (3-4)/6 = -1/6.
Since, both the resulting whole number (-1) and the resulting proper fraction (-1/6)
are both negative, it is the same as counting left of zero on a number line. Therefore,
-1 + (-1/6) = negative 1-and-1/6.