Misconception 1: Dividing by Any Common Number
A common mistake is dividing by any common factor, not the greatest one. For example, with 12/36, dividing by 2 gives 6/18. This is an equivalent fraction, but it's not fully simplified. You must continue dividing (e.g., by 6) to get 1/3. The correct method is to find the GCD (which is 12) and divide once: 12/12 = 1, 36/12 = 3, resulting in 1/3.
Misconception 2: Incorrectly Handling Negatives
The sign of a fraction is determined by the standard rules of division. A negative numerator and positive denominator result in a negative fraction. A negative numerator and negative denominator result in a positive fraction. For example, -5/10 simplifies to -1/2, while -5/-10 simplifies to 1/2. The standard convention is to place the negative sign in the numerator.
Misconception 3: What to Do with Improper Fractions
An improper fraction (like 10/4) should still be simplified first (to 5/2) before converting it to a mixed number (2 1/2). Don't convert to a mixed number first, as it can make simplification more confusing.