Zero Distance Slides Lesson 1 • Middle School Math
Distance Masters Series
Zero Distance
Discover why numbers care about how far they travel, not which direction they go.
Distance Concept
Steps from zero
Notation \(|x|\)
Absolute value bars
Real Scenarios
Elevation & depth
What is Absolute Value?
Distance is always positive or zero — never negative!
Core Concept
"How many steps is a number from 0?"
5 steps away
5 steps away
←
→
-5
-4
-3
-2
-1
0
1
2
3
4
+5
Both -5 and +5 are exactly 5 units away from 0.
\(|-5| = 5\) and \(|5| = 5\)
The Math Notation: \(|x|\)
Two straight vertical bars hug the number or expression.
Rules
Positive Input
Leaves the number unchanged.
\(|8| = 8\)
8 units to the right
Negative Input
Strips the negative sign away.
\(|-14| = 14\)
14 units to the left
Zero Input
Zero has no distance from itself.
\(|0| = 0\)
Zero steps
Remember: An absolute value output can NEVER be a negative number! Distance cannot be negative.
Real-World Magnitude
When we care about the amount, not the sign.
Applications
Sea Level vs. Submarine
A submarine is at an elevation of -280 meters.
Physical Depth:
\(|-280| = 280\text{ meters deep}\)
Bank Balance vs. Debt
Maya's account shows a balance of -$45.
Total Debt Owed:
\(|-45| = \$45\text{ owed}\)
Words like depth, debt, and difference describe absolute values!
The Danger Zone: Signs Outside!
Watch the position of the negative sign closely.
Common Trap
Negative Inside Standard
\(|-9| = 9\)
The absolute value operation acts first. The distance of -9 from 0 is positive 9 .
Negative Outside Opposite of...
\(-|-9| = -9\)
First evaluate \(|-9| = 9\). Then apply the negative sign waiting outside: result is -9 !
Treat absolute value bars like parentheses : evaluate what is inside first!
Quickfire Check
Discuss with your partner before voting on each value.
Partner Talk
1. Evaluate \(|-17|\)
?
2. Evaluate \(-|24|\)
?
3. True or False: \(|-6| = |6|\)
?
4. Distance between -3 and 0
?
Ready for the student worksheet! Keep your number lines handy
Zero Distance Student Worksheet Distance Masters • Lesson 1
Zero Distance: Finding Absolute Value
Name: ___________________________
Date: ____________ Period: _____
Key Idea: The absolute value of a number is its distance from zero on a number line. Distance is always non-negative. Notation: \(|x|\).
\(|-a| = |a| = a\)
1
Visual Number Lines
Draw an arc from 0 to each integer, state the number of steps, and complete the absolute value statement.
A. Plot and find the distance for -6:
Steps from 0: Statement: \(|-6| =\)
-8 -6 -4 -2 0 2 4 6 8
B. Plot and find the distance for +4:
Steps from 0: Statement: \(|4| =\)
-6 -4 -2 0 2 4 6
2
Evaluate Each Absolute Value
1. \(|19|\) =
2. \(|-31|\) =
3. \(|0|\) =
4. \(-|15|\) =
5. \(|-8.5|\) =
6. \(-|-42|\) =
7. \(|-\frac{3}{4}|\) =
8. \(-|0|\) =
3
Compare Values: Write \(<\), \(>\), or \(=\)
\(|-12|\) \(|12|\)
\(-15\) \(|-9|\)
\(-|7|\) \(-5\)
\(|-20|\) \(|18|\)
\(-|-8|\) \(|-8|\)
\(|0|\) \(-|2|\)
Distance Masters Series • Lesson 1 Student Worksheet Page 1 of 2
Lesson 1 • Applied Practice Name: ___________________________
4
Real-World Magnitude Problems
Model each scenario using an integer and its absolute value. Write complete explanations.
Badwater Basin in Death Valley sits at an elevation of -86 meters relative to sea level. Nearby Mount Whitney sits at +4,421 meters .
Depth/distance of Badwater Basin from sea level:
\(|\text{Elevation}| =\)
Which location has a greater distance from sea level?
Jordan has a bank balance of -$72 , while Samantha has a balance of -$45 .
Write absolute value expressions for the debt of each person:
Jordan: Samantha:
Who owes more money, and who has the greater account balance? Explain clearly:
5
Error Analysis: Help Detective Dani
Student Claim: "Since absolute value always turns negative signs into positive signs, \(-|-16| = +16\)!"
What is the error in the student's thinking?
What is the correct value of \(-|-16|\)?
Zero Distance Teacher Guide Teacher Resource • Distance Masters
Lesson 1: Distance from Zero Guide
Middle School Math (Grades 6–7)
Unit 1 • 45–50 Minutes
Learning Objectives
Define absolute value as non-negative distance from zero on a number line.
Evaluate numerical absolute values including positive, negative, and zero.
Distinguish between \(|-x|\) and \(-|x|\) and interpret real-world contexts.
Suggested Pacing
5 min: Hook & Number Line Walk
15 min: Slides & Notation
20 min: Guided & Paired Work
10 min: Reflection & Exit Check
Critical Misconception Alert
Students frequently overgeneralize that "absolute value makes every sign positive" . This causes errors on problems with leading negative signs outside the bars like \(-|15|\) or \(-|-16|\). Stress that absolute value acts as a grouping symbol first: \(|-16| = 16\), then the outer negative yields \(-16\).
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Student Worksheet Answer Key
Part 1: Number Lines
A. -6: 6 steps from 0; \(|-6| = 6\).
B. +4: 4 steps from 0; \(|4| = 4\).
Part 2: Core Values
1. 19 2. 31 3. 0 4. -15 5. 8.5 6. -42 7. 3/4 8. 0
Part 3: Comparisons
\(|-12| \mathbf{=} |12|\) (both 12)
\(-15 \mathbf{<} |-9|\) (-15 < 9)
\(-|7| \mathbf{<} -5\) (-7 < -5)
\(|-20| \mathbf{>} |18|\) (20 > 18)
\(-|-8| \mathbf{<} |-8|\) (-8 < 8)
\(|0| \mathbf{>} -|2|\) (0 > -2)
Part 4: Real-World Scenarios:
A. Death Valley: \(|-86| = 86\text{ m}\). Mount Whitney has a greater distance from sea level (\(|4,421| = 4,421\text{ m} > 86\text{ m}\)).
B. Debt: Jordan's debt is \(|-72| = \$72\); Samantha's debt is \(|-45| = \$45\). Jordan owes more money (\(72 > 45\)), but Samantha has a greater balance (\(-45 > -72\)).
Part 5 & 6: Error Analysis & Reflection:
Part 5 Error: The student removed both negative signs at once. Inside \(|-16| = 16\); the outside negative remains, resulting in \(-16\).
Part 6 Reflection: Both \(k\) and \(-k\) are situated the same number of units away from zero on the number line in opposite directions. Since distance ignores direction, \(|k| = |-k|\).
Magnitude Matchup Slides Lesson 2 • Middle School Math
Distance Masters Series
Expressions & Magnitude
Learn how absolute value bars work inside the Order of Operations and calculate distance between any two numbers!
Grouping Symbols
Inside first, then bars
Distance Formula
\(|a - b|\) on line
Change Scenarios
Temperature swings
Bars Are Grouping Symbols
In PEMDAS, absolute value bars act just like parentheses.
Rule #1
1 Simplify Inside
Complete all operations inside the bars first.
\(|4 - 11| \rightarrow |-7|\)
2 Take Distance
Apply the absolute value to make the inside positive.
\(|-7| \rightarrow 7\)
3 Finish Outer Math
Multiply, add, or subtract any numbers outside.
\(5 + 7 = 12\)
Never distribute into absolute value bars! Simplify the interior first. Inside → Absolute → Outside
Spot the Difference!
Where the bars sit completely changes the answer.
Look Closely
Case A: Subtraction Inside
\(|7 - 12|\)
• Compute inside first: \(7 - 12 = -5\)
• Apply absolute value: \(|-5| = \mathbf{5}\)
Result is 5 (positive distance)
Case B: Subtraction Outside
\(|7| - |12|\)
• Evaluate each bar first: \(7\) and \(12\)
• Subtract outside: \(7 - 12 = \mathbf{-5}\)
Result is -5 (subtraction gives negative)
Conclusion: \(|a - b| \neq |a| - |b|\). Always respect the grouping boundary!
Distance Between Two Numbers
Subtract the two values and take the absolute value.
Core Formula
The distance \(d\) between point \(a\) and point \(b\) is:
\(\text{Distance} = |a - b| = |b - a|\)
Option 1: \(|-4 - 6|\)
\(= |-10| = \mathbf{10\text{ units}}\)
Start from -4 and subtract 6
Option 2: \(|6 - (-4)|\)
\(= |6 + 4| = |10| = \mathbf{10\text{ units}}\)
Start from 6 and subtract -4
Order doesn't matter! The absolute value guarantees distance is identical in both directions.
Real-Life: Temperature Swings
Crossing zero on a thermometer.
Context
The Problem:
At 6:00 AM, the temperature in Minneapolis was . By 2:00 PM, it rose to .
Magnitude Matchup Student Worksheet Distance Masters • Lesson 2
Expressions and Magnitude
Name: ___________________________
Date: ____________ Period: _____
Order of Operations Rule: Treat bars \(| \dots |\) as grouping symbols. Simplify the inner expression first, take the absolute value, then apply outside operations.
Inside → Bars → Outside
1
Evaluate Each Numerical Expression
Show your step-by-step simplification on each line provided.
A. \(|4 - 11| + 6\)
Step 1: Simplify inside =
Step 2: Take absolute value =
Final Answer:
B. \(5 \cdot |-3| - 8\)
Step 1: Absolute value of -3 =
Step 2: Multiply by 5 =
Final Answer:
C. \(-|9 - 2| + 14\)
Step 1: Simplify inside =
Step 2: Apply outside sign =
Final Answer:
D. \(|16 - 25| \div 3\)
Step 1: Inside subtraction =
Step 2: Divide by 3 =
Final Answer:
2
True or False? Justify with Math
Statement: \(| -8 + 3 | = |-8| + |3|\)
Left side evaluates to: _____ • Right side evaluates to: _____
True False
Statement: \(| -5 \cdot 4 | = |-5| \cdot |4|\)
Left side evaluates to: _____ • Right side evaluates to: _____
True False
3
Evaluate with Variables
Let \(x = -5\) and \(y = 3\). Substitute and calculate:
1. \(|x| + |y|\)
2. \(|x - y|\)
3. \(-|2x + y|\)
Distance Masters Series • Lesson 2 Student Worksheet Page 1 of 2
Lesson 2 • Geometric Distance & Modeling Name: ___________________________
4
Distance Between Two Coordinates: \(d = |a - b|\)
Calculate the distance between points \(a\) and \(b\). Verify by showing your work.
| Point \(a\) | Point \(b\) | Absolute Value Setup \(|a - b|\) | Distance (Units) |
| --- | --- | --- | --- |
| -9 | 4 | \(|-9 - 4| = |-13|\) | 13 |
| -15 | -7 | \(|-15 - (-7)| =\) |
|
| 18 | -6 | \(|18 - (-6)| =\) |
|
| -24 | 11 |
|
|
5
Word Problems • Practical Distance
A. Fargo Winter Temperature Swing
At midnight, the thermometer read -14°F . By noon the following day, the temperature was 23°F .
Write an absolute value expression for the temperature swing:
Magnitude Matchup Teacher Guide Teacher Resource • Distance Masters
Lesson 2: Expressions & Magnitude Guide
Middle School Math (Grades 6–7)
Unit 2 • 45–50 Minutes
Learning Targets
Apply Order of Operations by simplifying within absolute value bars first.
Evaluate multi-step algebraic expressions with integer substitution.
Model and calculate the distance between any two coordinates using \(|a - b|\).
Instructional Flow
7 min: Grouping Warm-up
13 min: Slide Examples
20 min: Paired Worksheet
10 min: Debrief & Mystery Teaser
Instructional Tip: The Bridge to Equations
Notice Part 6 on the worksheet introduces \(|n - 4| = 9\). Use this as a natural conversational bridge to tomorrow's Lesson 3! Ask students: "If distance from 4 is 9 units, which way could you jump?" They will intuitively see you can jump 9 units right (\(4 + 9 = 13\)) or 9 units left (\(4 - 9 = -5\)). That sets up dual-branch solving without algebraic fear.
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Student Worksheet Answer Key
Part 1: Order of Operations
A. \(|4 - 11| + 6 = |-7| + 6 = 7 + 6 = \mathbf{13}\)
B. \(5 \cdot |-3| - 8 = 5(3) - 8 = 15 - 8 = \mathbf{7}\)
C. \(-|9 - 2| + 14 = -|7| + 14 = -7 + 14 = \mathbf{7}\)
D. \(|16 - 25| \div 3 = |-9| \div 3 = 9 \div 3 = \mathbf{3}\)
Part 2: True / False
Statement 1: False. Left side \(|-5| = 5\), but right side \(8 + 3 = 11\). (\(5 \neq 11\))
Statement 2: True. Left side \(|-20| = 20\), right side \(5 \cdot 4 = 20\).
Part 3: Variable Values (\(x=-5, y=3\))
1. \(|-5| + |3| = 5 + 3 = \mathbf{8}\)
2. \(|-5 - 3| = |-8| = \mathbf{8}\)
3. \(-|2(-5) + 3| = -|-10 + 3| = -|-7| = \mathbf{-7}\)
Part 4: Distance Table
• \((-15, -7)\): \(|-15 - (-7)| = |-8| = \mathbf{8}\)
• \((18, -6)\): \(|18 - (-6)| = |24| = \mathbf{24}\)
• \((-24, 11)\): \(|-24 - 11| = |-35| = \mathbf{35}\)
Part 5: Applications: A (Temperature): Expression \(|23 - (-14)| = |37| = 37^\circ\text{F}\) swing. B (Football): Total ball travel \(|-8| + |15| = 8 + 15 = 23\text{ yards}\). Net change \(-8 + 15 = +7\text{ yards}\) (now on 42-yard line).
Equation Split Slides Lesson 3 • Middle School Math
Distance Masters Series
Branching Equations
Why do absolute value equations produce two separate answers? Learn the branch method to find both!
Two Branches
Positive & negative
No Solution Trap
\(|x| = -k\) is impossible
Target Tolerance
Real engineering margins
Why Do We Get Two Answers?
Distance looks in both directions from the center.
Intuition
Solve this mystery equation:
\(|x| = 7\)
"What numbers are exactly 7 units away from zero?"
Branch 1: Walk Right
\(x = +7\)
Check: \(|7| = 7\) ✓
Branch 2: Walk Left
\(x = -7\)
Check: \(|-7| = 7\) ✓
Whenever the right side is a positive number \(c\), an absolute value equation splits into two branches!
Solving \(|x + 3| = 8\)
Drop the bars and split into positive and negative cases.
Algorithm
\(|x + 3| = 8\)
Positive Branch Inside = +8
\(x + 3 = 8\)
Subtract 3 from both sides:
\(x = 5\)
Negative Branch Inside = -8
\(x + 3 = -8\)
Subtract 3 from both sides:
\(x = -11\)
Solution Set: \(x = 5\) or \(x = -11\). Always check both back in the original equation!
Special Cases & Traps
Not every equation has two solutions!
Watch Out
Equal to a Negative 0 Solutions
\(|x - 4| = -6\)
Can distance ever be negative? NO! Stop immediately.
Answer: No Solution (\(\varnothing\))
Equal to Zero 1 Solution
\(|2x - 10| = 0\)
Zero has no sign (\(+0 = -0\)). There is only one branch to solve!
\(2x - 10 = 0 \implies x = 5\)
Check the right-hand constant before splitting: positive (2), zero (1), or negative (0)!
Engineering Tolerance
How factory machines and bakers use absolute value.
Application
The Scenario: Cereal Box Weight
A machine fills cereal boxes to an ideal target weight of 450 grams . The scale allows an error (tolerance) of at most 6 grams .
Equation for the boundary weights:
\(|\text{Weight} - \text{Target}| = \text{Tolerance}\)
Equation Split Student Worksheet Distance Masters • Lesson 3
Branching Equations
Name: ___________________________
Date: ____________ Period: _____
The Golden Branch Rule: When \(|X| = c\) and \(c > 0\), split into two linear equations : \(X = c\) OR \(X = -c\). If \(c < 0\), there is no solution !
1
Warm-up: Determine the Solution(s)
A. \(|x| = 14\)
Two numbers 14 units from 0:
\(x =\)
B. \(|m| = 0\)
Numbers 0 units from 0:
\(m =\)
C. \(|y| = -8\)
Can distance be negative?
\(y =\)
2
Split into Two Branches and Solve
Set up the positive branch and negative branch. Show each step clearly.
1. \(|x + 5| = 11\)
Positive Branch:
\(x + 5 = 11\)
\(x =\) _____
Negative Branch:
\(x + 5 = -11\)
\(x =\) _____
Check solutions: \(|(\dots) + 5| = 11\) ✓
2. \(|w - 7| = 4\)
Positive Branch:
\(w - 7 = 4\)
\(w =\) _____
Negative Branch:
\(w - 7 = -4\)
\(w =\) _____
Check solutions: \(|(\dots) - 7| = 4\) ✓
3. \(|2y - 6| = 12\)
Positive Branch:
\(2y - 6 = 12\)
\(y =\) _____
Negative Branch:
\(2y - 6 = -12\)
\(y =\) _____
Check solutions: \(|2(\dots) - 6| = 12\) ✓
4. \(|p + 2| - 5 = 3\) (Isolate bars first!)
Isolate: \(|p + 2| = 8\)
\(p + 2 = 8\)
\(p =\) _____
Negative Branch:
\(p + 2 = -8\)
\(p =\) _____
Check solutions: \(|(\dots) + 2| - 5 = 3\) ✓
3
Graph Solution Sets on Number Line
Graph the solution set of \(|x - 1| = 4\) (which gives \(x = 5\) and \(x = -3\)):
-5 -3 -1 1 3 5 7
Plot solid points at both solution coordinates. Notice that 1 is the exact midpoint!
Distance Masters Series • Lesson 3 Student Worksheet Page 1 of 2
Lesson 3 • Analysis & Engineering Tolerance Name: ___________________________
4
Identify Number of Solutions (0, 1, or 2)
State the number of solutions without solving fully, and explain your reasoning.
Equation Split Teacher Guide Teacher Resource • Distance Masters
Lesson 3: Branching Equations Guide
Middle School Math (Grades 6–8)
Unit 3 • 45–50 Minutes
Learning Targets
Isolate absolute value bars and split into positive/negative linear branches.
Recognize equations with no solution (\(|X| = -c\)) and one solution (\(|X| = 0\)).
Model physical tolerances using \(|\text{actual} - \text{target}| = \text{tolerance}\).
Instructional Flow
5 min: Two-Way Intuition Warm-up
15 min: Slide Walkthrough & Branching
20 min: Guided & Independent Worksheet
10 min: Unit Synthesis & Exit Ticket
Critical Pitfall: Premature Splitting
Students frequently attempt to branch before isolating the absolute value bars. For example, with \(|p + 2| - 5 = 3\), a student might incorrectly write \(p + 2 - 5 = 3\) and \(p + 2 - 5 = -3\). Emphasize: The bars must stand alone on one side of the equal sign before opening the two branches!
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Student Worksheet Answer Key
Part 1: Warm-up Solutions
A. \(|x| = 14 \implies \mathbf{x = 14 \text{ or } -14}\)
B. \(|m| = 0 \implies \mathbf{m = 0}\) (single solution)
C. \(|y| = -8 \implies \mathbf{\text{No solution}}\) (distance ≥ 0)
Part 2: Two-Branch Solving
1. \(x + 5 = 11 \implies x = 6\); \(x + 5 = -11 \implies \mathbf{x = -16}\)
2. \(w - 7 = 4 \implies w = 11\); \(w - 7 = -4 \implies \mathbf{w = 3}\)
3. \(2y - 6 = 12 \implies 2y = 18 \implies y = 9\); \(2y - 6 = -12 \implies 2y = -6 \implies \mathbf{y = -3}\)
4. \(|p + 2| = 8 \implies p = 6\text{ or }\mathbf{p = -10}\)
Part 3: Solution Graphing
Solid plotted points at \(\mathbf{-3}\) and \(\mathbf{5}\). Note center is \(1\), and both dots are exactly 4 units away from 1.
Part 4: Solution Count
• \(|3x - 12| = 0 \implies \mathbf{1\text{ sol}}\) (\(3x = 12 \implies x = 4\))
• \(|y - 15| = 22 \implies \mathbf{2\text{ sol}}\) (positive constant)
• \(|m + 6| + 7 = 3 \implies |m + 6| = -4 \implies \mathbf{0\text{ sol}}\)
Part 5: Tolerance Modeling: A (Flight): Equation \(|h - 33,000| = 400\). Min altitude \(= 33,000 - 400 = \mathbf{32,600\text{ ft}}\); Max \(= 33,000 + 400 = \mathbf{33,400\text{ ft}}\). Equation \(|T - 238| = 3\). Min temp \(= 238 - 3 = \mathbf{235^\circ\text{F}}\); Max \(= 238 + 3 = \mathbf{241^\circ\text{F}}\).