Subtracting a rational number is the same as adding it's opposite. If you have a double negative , you add it like it is a positive , than keep the answer you get. Examples:
1) 6 3/4 - (-8 4/8) is the same as saying 6 3/4 ÷ 8 4/8.
2) -38 5/8 - 6 5/12 translates to -38 5/8 + (-6 5/12)
