Mathematics » Number Theory » Understanding Absolute Value
ABSOLUTE VALUE
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Quick Summary
Absolute value represents distance from zero. It is denoted by vertical bars: |x|. The absolute value of a number is always non-negative.
\[ |x| = \begin{cases} x, & \text{if } x \geq 0 \\ -x, & \text{if } x < 0 \end{cases} \]
⚠️ Common Mistakes
Assuming absolute value always makes a number positive (e.g., |-x| = x is not always true). Forgetting to consider both positive and negative cases when solving equations involving absolute value. Incorrectly applying the definition when dealing with variables.
🌍 Real-World Uses
Calculating distances regardless of direction. Error analysis in measurements. Determining tolerances in engineering designs.
📝 Practice Problems
Problem 1: Evaluate |-5|.
Solution: The distance of -5 from zero is 5, so |-5| = 5.
Problem 2: Evaluate |3 - 7|.
Solution: |3 - 7| = |-4| = 4.
📋 Standards Alignment
CCSS.MATH.CONTENT.6.NS.C.7.CCCSS.MATH.CONTENT.7.NS.A.1
🔗 Related Links
🍎 Teacher Insights
Use a number line to visually demonstrate the concept of distance from zero. Emphasize the importance of considering both positive and negative cases when solving absolute value equations.
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Frequently Asked Questions
Q: What is the absolute value of zero? A: The absolute value of zero is zero, |0| = 0.
Q: Can an absolute value be negative? A: No, the absolute value of a number is always non-negative.