Introduction to Inequalities

Introduction

Inequalities are statements that compare two numbers or expressions.
They tell us whether one quantity is greater than, less than, or sometimes equal to another.

In this article, you will learn:

This article assumes you already know basic arithmetic (addition, subtraction, multiplication, division).

What Are Inequalities?

An inequality is a mathematical comparison between two values.

The two most common symbols are:

Key ideas:

How to Read Inequalities

Some helpful reading patterns:

Tips:

Examples:

Comparing Numbers

To decide whether $a > b$ or $a < b$, you can:

Examples:

Writing Your Own Inequalities

You can express real-world comparisons using inequalities.

Examples:

Guidelines:

Greater Than or Equal To (≥) and Less Than or Equal To (≤)

So far, you’ve seen inequalities that compare two values strictly using greater than (>) and less than (<). But sometimes two quantities can be equal as well as greater or less.
That’s where the symbols and come in.

What the Symbols Mean

Examples

How to Read Them

A helpful reminder:
The line under the symbol means equality is allowed.

Why These Symbols Matter

In many real‑world situations, you want to include the possibility of equality:

Drawing inequalities

All four inequalities on the same number line

Calculator

Evaluating inequalities

  • The calculator can be used to evaluate inequalities, returning either true or false.
  • To represent $\ge$ and $\le$ we use >= and <= respectively.
3 < 4 5 < 4 3 <= 3 3 >= 3 5 >= 6 6 > 5

Exercises

  1. Decide whether the statement $8 > 5$ is true or false.

    Solution

    True.
    $8$ is greater than $5$.
  2. Fill in the blank with $>$ or $<$: $3 \; \_ \; 9$

    Solution

    $3 < 9$
    Because 3 is less than 9.
  3. Compare the numbers: Is $-4$ greater than or less than $2$?

    Solution

    $-4 < 2$
    Negative numbers are always less than positive numbers.
  4. Write an inequality comparing $7$ and $12$.

    Solution

    $7 < 12$
    Because 7 is smaller.
  5. Determine whether $0.8 < 0.5$ is true or false.

    Solution

    False.
    $0.8$ is greater than $0.5$, so $0.8 < 0.5$ is not true.
  6. Fill in the blank: $15 \; \_ \; 10$

    Solution

    $15 > 10$
    Because 15 is greater.
  7. Compare the temperatures: $-3^\circ$C and $4^\circ$C.

    Solution

    $-3 < 4$
    Negative temperatures are less than positive ones.
  8. Decide whether the statement $14 \le 9$ is true or false.

    Solution

    False.
    Fourteen is greater than nine, so “less than or equal to” is not true.
  9. Fill in the blank with $\ge$ or $\le$: $$-2 \;\_\; 5$$

    Solution

    $ -2 \le 5 $
    Negative numbers are always less than positive numbers.
  10. Compare the numbers and write a true inequality: $$3 \text{ and } 3$$

    Solution

    $ 3 \ge 3 $ or $ 3 \le 3 $
    Since the numbers are equal, both symbols with equality allowed are correct.