Equal, Less Than, Greater Than — Definition, Formula & Examples
Equal, less than, and greater than are the three basic comparison symbols used to show how two numbers relate to each other. The equal sign (=) means two values are the same, the less than sign (<) means the first number is smaller, and the greater than sign (>) means the first number is larger.
For any two real numbers and , exactly one of three relationships holds: (the quantities are identical in value), (the value of is strictly less than the value of ), or (the value of is strictly greater than the value of ). This principle is known as the trichotomy property of real numbers. The symbols and are called inequality signs, while is the equality sign.
Key Formula
Where:
- = The first number being compared
- = The second number being compared
- = Means a is less than b (a is smaller)
- = Means a equals b (same value)
- = Means a is greater than b (a is larger)
How It Works
To compare two numbers, picture them on a number line: the number farther to the right is greater, and the number farther to the left is less. If they sit at the same point, they are equal. A helpful trick for the and symbols is that the pointed end always faces the smaller number, like an arrow pointing at it. You can also think of the symbol as a hungry alligator mouth that always opens toward the bigger number. When you write , you read it left to right as "3 is less than 7." When you write , you read it as "7 is greater than 3."
Worked Example
Problem: Compare the numbers 12 and 5 using the correct symbol.
Step 1: Identify which number is larger. 12 is farther to the right on a number line than 5, so 12 is the larger number.
Step 2: Choose the correct symbol. Since 12 is larger than 5, we use the greater than sign (>). Remember, the open side of the symbol faces the bigger number.
Step 3: Write the comparison.
Answer: — twelve is greater than five.
Another Example
This example involves an expression on one side that must be evaluated before comparing, and the result is equality rather than an inequality.
Problem: Fill in the blank with =, <, or >: 4 + 6 ___ 10
Step 1: Simplify the left side. Add 4 and 6.
Step 2: Now compare 10 and 10. Both values are the same.
Step 3: Since the values are identical, use the equal sign.
Answer:
Why It Matters
Comparison symbols appear in every math course from first grade through calculus, making them one of the most frequently used pieces of notation in all of mathematics. Understanding , , and is the foundation for solving inequalities, writing compound inequalities, and interpreting interval notation in algebra. Outside school, you compare quantities whenever you check prices, read temperatures, or evaluate sports statistics.
Common Mistakes
Mistake: Mixing up the direction of < and >
Correction: Remember: the pointed end always aims at the smaller number. If you write 8 < 3, that says 8 is smaller than 3, which is wrong. It should be 8 > 3.
Mistake: Thinking a bigger-looking digit means a bigger number when negatives are involved
Correction: With negative numbers, a larger digit actually means a smaller value. For example, even though 10 looks bigger than 2. Always check position on a number line.
Mistake: Using the equal sign when values are only close, not exactly the same
Correction: The equal sign means the two sides have the exact same value. If and , then ; you must write .
Check Your Understanding
Fill in the blank with <, =, or >: 9 ___ 15
Hint: Which number is farther to the right on a number line?
Answer:
True or false:
Hint: Draw a number line and plot both numbers.
Answer: False. because is farther to the left on a number line.
Fill in the blank: ___
Hint: Calculate each side first, then compare.
Answer: because both sides equal 10.
