What are the rules for subtracting positive and negative numbers?

Adding/ Subtracting Mixed Numbers Help!!?

• it's really easy but my brain's just dormant..this is the exact question: Describe at least two things that you have to think about when you add or subtract MIXED NUMBERS that you DON'T have to think about when adding or subtracting FRACTIONS. i already came up with one thing, i just need one more please help {p.s. i already put how in subtracting mixed numbers, the greater number's numerator may be less than the less numbers numerator} Please and thanks!

• Answer:

  1) Changing the whole-number parts into improper fractions with equal denominators (e.g., 73/6 -15/6). OR 2) Changing only the fractional parts to fractions with common denominators using the least common multiple method (e.g., 6 4/7 - 4 3/7). AND 3) Subtracting or adding either numerators of improper fractions (e.g., 58/6) or both whole and fractional parts separately (e.g., 2 1/7) and simplifying. As for differences between that and normal fraction subtraction, I think the fact that you have to convert whole numbers to fractions is one, plus the fact that you may have to convert back to mixed numbers at the end.