Stage 4 · Easier Concepts You Might Not Know

Absolute Value

Absolute value measures distance — and distance is always positive. This skill shows up in GED problems about elevation, temperature, money, and direction. Learn to recognize it even when the words "absolute value" never appear.

📖 The Lesson

Absolute value answers one question: how far? It tells you the distance between two numbers on a number line — and distance is always a positive number, no matter which direction you go.

The absolute value bars look like this: | |   Whatever is inside gets its distance from zero. So |−7| = 7 because −7 is 7 steps from zero. And |7| = 7 for the same reason — just in the other direction.

Distance from zero
|−7| = 7   |7| = 7
Both −7 and 7 are exactly 7 steps from zero on the number line. The absolute value bars drop the negative sign and give you the distance.
Distance between two numbers
|a − b| or |b − a|
Either order works. The absolute value takes care of the sign. Both give the same distance — the bars make it positive either way.

↔ Two Ways to Write the Same Distance

When you need the distance between two numbers, you can subtract them in either order — as long as you put the whole expression inside absolute value bars. Both expressions are correct and give the same answer.

Worked Example — Distance Between −3 and 5

What is the distance between −3 and 5 on a number line?

Option 1: |−3 − 5| = |−8| = 8
Option 2: |5 − (−3)| = |5 + 3| = |8| = 8
Distance = 8

Both expressions give 8. The GED may ask you to pick the correct expression — not calculate the answer. Know that both forms are valid.

GED Tip: Some questions will show you the absolute value expression and ask which one correctly represents the distance. They won't ask you to solve it — just identify it. Make sure the two numbers in the bars match the numbers in the problem, and that they are subtracted, not added.

🌍 Why This Shows Up in Real Life

In everyday life, we almost never say "negative." We say below, under, down, behind, in debt, lower than. The direction is built into the word — but the distance is just the number.

If one person is 25 and another is 31, we say they are 6 years apart — not "positive 6" or "negative 6." The absolute value gives us that plain number.

Same with directions. We don't say "negative 4 blocks." We say 4 blocks east, 4 blocks back, 4 feet below sea level. The word tells the direction. The absolute value gives the distance.

Worked Example — Elevation Word Problem

A hiker is at 340 feet above sea level. A submarine is 85 feet below sea level. What is the distance between their elevations?

Above sea level = positive: +340
Below sea level = negative: −85
Distance = |340 − (−85)| = |340 + 85| = |425| = 425
Distance = 425 feet
No-calculator tip: When you subtract a negative, change it to addition. −(−85) becomes +85. This is the most common arithmetic mistake on absolute value problems — watch for it.
Worked Example — Temperature Change

The temperature on Monday was −4°F. On Tuesday it was 17°F. How many degrees did the temperature change?

|17 − (−4)| = |17 + 4| = |21| = 21
Temperature changed by 21 degrees

📝 Summary

Absolute value = distance. Distance is always positive. To find the distance between two numbers, subtract them in either order and put the result inside absolute value bars. On the GED, this skill hides inside problems about elevation, temperature, money, direction, and floors in a building. Watch for words like below, beneath, under, down, in debt, lower than — those signal a negative number.

Two correct forms: |a − b| and |b − a| both give the same distance. If the GED asks you to identify the correct expression, look for the one that has the two given numbers subtracted — in either order — inside the bars.

✏️ Practice Questions

Bank 1 — Number Line Distance
Choose the expression that correctly represents the distance · No calculator needed
You've answered 5 questions. Keep going or check your score.
Bank 2 — Real-World Word Problems
Elevation, temperature, money, and more · No calculator needed
You've answered 5 questions. Keep going or check your score.
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Undefined Expressions
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