Common Pre-Algebra Mistakes
Example: Simplifying a Fraction

The Goal

Simplify the expression:


The Mistake

What the student wrote:


With a step added to show what it appears was computed in the student's head, find the mistake:


(Roll the mouse over the algebra to see a hint in red)

The Correction


(Roll the mouse over the area above to see the correction in blue)

An Explanation

Use care with signs. A good strategy is to write down intermediate steps, which makes you take the time needed to simplify correctly.

Visit Algebra Facts > Adding and subtracting fractions to learn more.

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