Inequality Intuition Examples in Math

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Inequality Intuition.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Math.

Concept Recap

Understanding that << and >> describe ordering relationships—one quantity is strictly smaller or larger than the other.

If 5<75 < 7, then 5 is somewhere to the left of 7 on the number line.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: An inequality with << or >> says one quantity is definitely smaller or larger, fixing their order on the number line.

Common stuck point: The procedure for inequality intuition is the easy part; the trap is forgetting to flip the symbol when multiplying or dividing by a negative. Asking "Does the statement order two quantities (strictly smaller or larger) rather than equate them?" first is what keeps a correct-looking calculation from being attached to the wrong concept.

Sense of Study hint: Ask: Does the statement order two quantities (strictly smaller or larger) rather than equate them?

Worked Examples

Example 1

easy
Solve x+3<10x + 3 < 10 and graph the solution on a number line.

Answer

x<7x < 7

First step

1
Subtract 3 from both sides: x<7x < 7.

Full solution

  1. 2
    Solution: all numbers less than 7.
  2. 3
    Graph: open circle at 7, arrow pointing left.
  3. 4
    Example values: x=6,5,0,1,x = 6, 5, 0, -1, \ldots
Inequalities are solved like equations but with a direction. The solution is a range of values, not a single point. Open circle means 7 is not included.

Example 2

medium
Solve 2x8-2x \geq 8 and explain the direction flip when multiplying by a negative.

Example 3

easy
Solve x52x - 5 \geq -2 and show on a number line.

Example 4

medium
Explain why a<ba < b implies a+c<b+ca + c < b + c for any real cc.

Example 5

medium
Show on a number line: x>1x > -1 and x4x \leq 4. Write the intersection.

Example 6

challenge
Prove: if a,b>0a, b > 0, then a+b2aba + b \geq 2\sqrt{ab}.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Solve 2x4>62x - 4 > 6.

Example 2

medium
A student must score at least 70 to pass. They have scores 65, 72, 80. Which scores pass? Write as inequalities.

Example 3

easy
Which symbol makes it true: 5  85 \ \square\ 8?

Example 4

easy
Read 3>x3 > x in words.

Example 5

easy
Does x5x \le 5 include the value 55?

Example 6

easy
Does x<5x < 5 include the value 55?

Example 7

easy
On a number line, is 3-3 to the left or right of 22?

Example 8

easy
Which is true: 5<2-5 < -2 or 5>2-5 > -2?

Example 9

easy
Is x0x \ge 0 satisfied by x=0x = 0?

Example 10

easy
Rewrite 7>x7 > x with the variable on the left.

Example 11

medium
Solve x+3<10x + 3 < 10.

Example 12

medium
Solve 2x>6-2x > 6.

Example 13

medium
Solve 3x183x - 1 \ge 8.

Example 14

medium
Which integers satisfy 1<x3-1 < x \le 3?

Example 15

medium
Solve 5x25 - x \le 2.

Example 16

medium
A ride requires height 48\ge 48 inches. Write the inequality and state if 4848 inches qualifies.

Example 17

medium
Order from least to greatest: 32, 0.5, 1, 2-\frac{3}{2},\ 0.5,\ -1,\ 2.

Example 18

challenge
Solve 3<2x+17-3 < 2x + 1 \le 7 and give the integer solutions.

Example 19

challenge
For which values of xx is 2x+1>5-2x + 1 > 5? Explain the sign flip.

Example 20

challenge
Explain why multiplying both sides of 2<42 < 4 by 1-1 gives 2>4-2 > -4, not 2<4-2 < -4.

Example 21

medium
Solve x2+1<4\frac{x}{2} + 1 < 4.

Example 22

medium
A number nn satisfies 'at most 1010 and more than 44'. Write the compound inequality.

Example 23

easy
True or false: x4x \geq 4 is satisfied by x=4x = 4.

Example 24

easy
List the integers that satisfy 2x<2-2 \leq x < 2.

Example 25

easy
Order from least to greatest: 12,34,0,1\frac{1}{2}, -\frac{3}{4}, 0, -1.

Example 26

easy
Translate: 'a price pp no more than $50' as an inequality.

Example 27

medium
Solve 3x9-3x \leq 9.

Example 28

medium
Solve 2(x+1)3x42(x+1) \leq 3x - 4.

Example 29

medium
If a>ba > b and b>cb > c, what can you conclude about aa and cc?

Example 30

medium
A car uses up to 1212 gallons per trip and contains gg gallons. Write an inequality for safe fuel.

Example 31

medium
Which of the following violates x<3|x| < 3: x=2.9x = 2.9, x=3x = 3, x=2x = -2?

Example 32

medium
Solve x2>4\frac{x}{-2} > 4.

Example 33

medium
True or false: if a<ba < b then a2<b2a^2 < b^2.

Example 34

medium
How many positive integers nn satisfy n<7n < 7?

Example 35

hard
Solve the compound inequality 5<12x3-5 < 1 - 2x \leq 3.

Example 36

hard
If 2<x<5-2 < x < 5, find the range of 32x3 - 2x.

Example 37

hard
For which positive integers nn does 1n>110\frac{1}{n} > \frac{1}{10}?

Example 38

hard
A student claims: 'If a<ba < b then 1a>1b\frac{1}{a} > \frac{1}{b}.' Give a counterexample.

Example 39

challenge
For which real xx is xx21\frac{x}{x - 2} \leq 1?

Background Knowledge

These ideas may be useful before you work through the harder examples.

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